troll-patrol/src/tests.rs

#![allow(non_snake_case)]

use crate::{
    analysis::{blocked_in, Analyzer},
    bridge_verification_info::BridgeVerificationInfo,
    *,
};
use lox_library::{
    bridge_table::{self, BridgeLine, BridgeTable},
    cred::Lox,
    proto::*,
    scalar_u32, BridgeAuth, BridgeDb,
};

use base64::{engine::general_purpose, Engine as _};
use curve25519_dalek::{ristretto::RistrettoBasepointTable, Scalar};
use rand::RngCore;
use sha1::{Digest, Sha1};
use std::{
    collections::{BTreeMap, HashMap, HashSet},
    sync::{Arc, Mutex},
};
use x25519_dalek::{PublicKey, StaticSecret};

struct TestHarness {
    bdb: BridgeDb,
    pub ba: BridgeAuth,
}

impl TestHarness {
    fn new() -> Self {
        TestHarness::new_buckets(5, 5)
    }

    fn new_buckets(num_buckets: u16, hot_spare: u16) -> Self {
        // Create a BridegDb
        let mut bdb = BridgeDb::new();
        // Create a BridgeAuth
        let mut ba = BridgeAuth::new(bdb.pubkey);

        // Make 3 x num_buckets open invitation bridges, in sets of 3
        for _ in 0..num_buckets {
            let bucket = [random(), random(), random()];
            let _ = ba.add_openinv_bridges(bucket, &mut bdb);
        }
        // Add hot_spare more hot spare buckets
        for _ in 0..hot_spare {
            let bucket = [random(), random(), random()];
            let _ = ba.add_spare_bucket(bucket, &mut bdb);
        }
        // Create the encrypted bridge table
        ba.enc_bridge_table();

        Self { bdb, ba }
    }

    fn advance_days(&mut self, days: u16) {
        self.ba.advance_days(days);
    }

    fn get_new_credential(&mut self) -> Lox {
        let inv = self.bdb.invite().unwrap();
        let (req, state) = open_invite::request(&inv);
        let resp = self.ba.handle_open_invite(req).unwrap();
        let (cred, _bridgeline) =
            open_invite::handle_response(state, resp, &self.ba.lox_pub).unwrap();
        cred
    }

    fn level_up(&mut self, cred: &Lox) -> Lox {
        let current_level = scalar_u32(&cred.trust_level).unwrap();
        if current_level == 0 {
            self.advance_days(trust_promotion::UNTRUSTED_INTERVAL.try_into().unwrap());
            let (promreq, promstate) =
                trust_promotion::request(cred, &self.ba.lox_pub, self.ba.today()).unwrap();
            let promresp = self.ba.handle_trust_promotion(promreq).unwrap();
            let migcred = trust_promotion::handle_response(promstate, promresp).unwrap();
            let (migreq, migstate) =
                migration::request(cred, &migcred, &self.ba.lox_pub, &self.ba.migration_pub)
                    .unwrap();
            let migresp = self.ba.handle_migration(migreq).unwrap();
            let new_cred = migration::handle_response(migstate, migresp, &self.ba.lox_pub).unwrap();
            new_cred
        } else {
            self.advance_days(
                level_up::LEVEL_INTERVAL[usize::try_from(current_level).unwrap()]
                    .try_into()
                    .unwrap(),
            );
            let (id, key) = bridge_table::from_scalar(cred.bucket).unwrap();
            let encbuckets = self.ba.enc_bridge_table();
            let bucket =
                bridge_table::BridgeTable::decrypt_bucket(id, &key, encbuckets.get(&id).unwrap())
                    .unwrap();
            let reachcred = bucket.1.unwrap();
            let (lvreq, lvstate) = level_up::request(
                cred,
                &reachcred,
                &self.ba.lox_pub,
                &self.ba.reachability_pub,
                self.ba.today(),
            )
            .unwrap();
            let lvresp = self.ba.handle_level_up(lvreq).unwrap();
            let new_cred = level_up::handle_response(lvstate, lvresp, &self.ba.lox_pub).unwrap();
            new_cred
        }
    }

    fn get_bucket(&mut self, cred: &Lox) -> [BridgeLine; bridge_table::MAX_BRIDGES_PER_BUCKET] {
        let (id, key) = bridge_table::from_scalar(cred.bucket).unwrap();
        let encbuckets = self.ba.enc_bridge_table();
        let bucket =
            bridge_table::BridgeTable::decrypt_bucket(id, &key, encbuckets.get(&id).unwrap())
                .unwrap();
        bucket.0
    }
}

pub fn random() -> BridgeLine {
    let mut rng = rand::thread_rng();
    let mut res: BridgeLine = BridgeLine::default();
    // Pick a random 4-byte address
    let mut addr: [u8; 4] = [0; 4];
    rng.fill_bytes(&mut addr);
    // If the leading byte is 224 or more, that's not a valid IPv4
    // address.  Choose an IPv6 address instead (but don't worry too
    // much about it being well formed).
    if addr[0] >= 224 {
        rng.fill_bytes(&mut res.addr);
    } else {
        // Store an IPv4 address as a v4-mapped IPv6 address
        res.addr[10] = 255;
        res.addr[11] = 255;
        res.addr[12..16].copy_from_slice(&addr);
    };
    let ports: [u16; 4] = [443, 4433, 8080, 43079];
    let portidx = (rng.next_u32() % 4) as usize;
    res.port = ports[portidx];
    res.uid_fingerprint = rng.next_u64();
    rng.fill_bytes(&mut res.fingerprint);
    let mut cert: [u8; 52] = [0; 52];
    rng.fill_bytes(&mut cert);
    let infostr: String = format!(
        "obfs4 cert={}, iat-mode=0",
        general_purpose::STANDARD_NO_PAD.encode(cert)
    );
    res.info[..infostr.len()].copy_from_slice(infostr.as_bytes());
    res
}

#[tokio::test]
async fn test_extra_infos() {
    let bridge_to_test =
        array_bytes::hex2array("72E12B89136B45BBC81D1EF0AC7DDDBB91B148DB").unwrap();

    // Open test database
    let db: Db = sled::open("test_db_ei").unwrap();

    // Delete all data in test DB
    db.clear().unwrap();
    assert!(!db.contains_key("bridges").unwrap());
    assert!(!db.contains_key(bridge_to_test).unwrap());

    // Download and process recent extra-infos files
    update_extra_infos(
        &db,
        "https://collector.torproject.org/recent/bridge-descriptors/extra-infos/",
    )
    .await
    .unwrap();

    // Check that DB contains information on a bridge with high uptime
    assert!(db.contains_key("bridges").unwrap());
    let bridges: HashSet<[u8; 20]> =
        bincode::deserialize(&db.get("bridges").unwrap().unwrap()).unwrap();
    assert!(bridges.contains(&bridge_to_test));
    assert!(db.contains_key(bridge_to_test).unwrap());
    let _bridge_info: BridgeInfo =
        bincode::deserialize(&db.get(bridge_to_test).unwrap().unwrap()).unwrap();
}

#[test]
fn test_negative_reports() {
    let mut th = TestHarness::new();

    // Get new level 1 credential
    let cred = th.get_new_credential();
    let cred = th.level_up(&cred);

    let bridges = th.get_bucket(&cred);

    // Create BridgeVerificationInfo for each bridge
    let mut buckets = HashSet::<Scalar>::new();
    buckets.insert(cred.bucket);
    let bridge_info_1 = BridgeVerificationInfo {
        bridge_line: bridges[0],
        buckets: buckets.clone(),
        pubkey: None,
    };
    let bridge_info_2 = BridgeVerificationInfo {
        bridge_line: bridges[1],
        buckets: buckets.clone(),
        pubkey: None,
    };
    let bridge_info_3 = BridgeVerificationInfo {
        bridge_line: bridges[2],
        buckets: buckets.clone(),
        pubkey: None,
    };

    // Create reports
    let report_1 =
        NegativeReport::from_bridgeline(bridges[0], "ru".to_string(), BridgeDistributor::Lox);
    let report_2 =
        NegativeReport::from_lox_bucket(bridges[1].fingerprint, cred.bucket, "ru".to_string());
    let report_3 =
        NegativeReport::from_lox_credential(bridges[2].fingerprint, &cred, "ru".to_string());

    // Backdated reports
    let date = get_date();
    let mut rng = rand::thread_rng();

    let mut nonce = [0; 32];
    rng.fill_bytes(&mut nonce);
    let report_4 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(
            &bridges[0],
            date - 1,
            nonce,
        )),
        "ru".to_string(),
        date - 1,
        nonce,
        BridgeDistributor::Lox,
    );

    let mut nonce = [0; 32];
    rng.fill_bytes(&mut nonce);
    let report_5 = NegativeReport::new(
        bridges[1].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(
            &bridges[1],
            date - 2,
            nonce,
        )),
        "ru".to_string(),
        date - 2,
        nonce,
        BridgeDistributor::Lox,
    );

    let mut nonce = [0; 32];
    rng.fill_bytes(&mut nonce);
    let report_6 = NegativeReport::new(
        bridges[2].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(
            &bridges[2],
            date - 3,
            nonce,
        )),
        "ru".to_string(),
        date - 3,
        nonce,
        BridgeDistributor::Lox,
    );

    // Verify reports
    assert!(report_1.verify(&bridge_info_1));
    assert!(report_2.verify(&bridge_info_2));
    assert!(report_3.verify(&bridge_info_3));
    assert!(report_4.verify(&bridge_info_1));
    assert!(report_5.verify(&bridge_info_2));
    assert!(report_6.verify(&bridge_info_3));

    // Check that deserialization fails under invalid conditions

    // Date in the future
    let mut invalid_report_1 =
        NegativeReport::from_bridgeline(bridges[0], "ru".to_string(), BridgeDistributor::Lox)
            .to_serializable_report();
    invalid_report_1.date = invalid_report_1.date + 2;

    // Date too far in past
    let mut invalid_report_2 =
        NegativeReport::from_bridgeline(bridges[1], "ru".to_string(), BridgeDistributor::Lox)
            .to_serializable_report();
    invalid_report_2.date = invalid_report_2.date - MAX_BACKDATE - 1;

    // Invalid country code
    let invalid_report_3 =
        NegativeReport::from_bridgeline(bridges[2], "xx".to_string(), BridgeDistributor::Lox)
            .to_serializable_report();

    assert!(invalid_report_1.to_report().is_err());
    assert!(invalid_report_2.to_report().is_err());
    assert!(invalid_report_3.to_report().is_err());

    // Check that verification fails with incorrect data

    let date = get_date();
    let mut rng = rand::thread_rng();

    // Incorrect BridgeLine hash
    let mut nonce = [0; 32];
    rng.fill_bytes(&mut nonce);
    let invalid_report_4 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(
            &BridgeLine::default(),
            date,
            nonce,
        )),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    // Incorrect bucket hash
    let mut nonce = [0; 32];
    rng.fill_bytes(&mut nonce);
    let invalid_report_5 = NegativeReport::new(
        bridges[1].fingerprint,
        ProofOfBridgeKnowledge::HashOfBucket(HashOfBucket::new(&Scalar::ZERO, date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    assert!(!invalid_report_4.verify(&bridge_info_1));
    assert!(!invalid_report_5.verify(&bridge_info_2));

    // Test that reports with duplicate nonces are rejected
    // (Also test encryption and decryption.)

    // Open test database
    let db: Db = sled::open("test_db_nr").unwrap();

    // Delete all data in test DB
    db.clear().unwrap();
    assert!(!db.contains_key("nrs-to-process").unwrap());

    let mut nonce = [0; 32];
    rng.fill_bytes(&mut nonce);

    // A valid report
    let valid_report_1 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(&bridges[0], date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    let valid_report_1_copy_1 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(&bridges[0], date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    let valid_report_1_copy_2 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(&bridges[0], date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    // Report which reuses this nonce
    let invalid_report_1 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(&bridges[0], date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    // This is the same report
    assert_eq!(valid_report_1, invalid_report_1);

    // Report which reuses this nonce for a different bridge
    let invalid_report_2 = NegativeReport::new(
        bridges[1].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(&bridges[1], date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    // Report which uses this nonce but on a different day
    let valid_report_2 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(
            &bridges[0],
            date - 1,
            nonce,
        )),
        "ru".to_string(),
        date - 1,
        nonce,
        BridgeDistributor::Lox,
    );

    // Report with different nonce
    let mut nonce = [0; 32];
    rng.fill_bytes(&mut nonce);

    let valid_report_3 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBridgeLine(HashOfBridgeLine::new(&bridges[0], date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    let map_key_1 = format!(
        "{}_{}_{}",
        array_bytes::bytes2hex("", valid_report_1.fingerprint),
        "ru".to_string(),
        date
    );

    // Generate key for today
    let secret = StaticSecret::random_from_rng(&mut rng);
    let public = PublicKey::from(&secret);
    let secret_yesterday = StaticSecret::random_from_rng(&mut rng);
    let public_yesterday = PublicKey::from(&secret_yesterday);
    assert!(!db.contains_key("nr-keys").unwrap());

    // Fail to add to database because we can't decrypt
    handle_encrypted_negative_report(&db, valid_report_1_copy_1.encrypt(&public));
    assert!(!db.contains_key("nrs-to-process").unwrap());

    // Store yesterday's key but not today's
    let mut nr_keys = BTreeMap::<u32, StaticSecret>::new();
    nr_keys.insert(date - 1, secret_yesterday);
    db.insert("nr-keys", bincode::serialize(&nr_keys).unwrap())
        .unwrap();

    // Fail to add to database because we still can't decrypt
    handle_encrypted_negative_report(&db, valid_report_1_copy_2.encrypt(&public));
    assert!(!db.contains_key("nrs-to-process").unwrap());

    // Store today's key
    nr_keys.insert(date, secret);
    db.insert("nr-keys", bincode::serialize(&nr_keys).unwrap())
        .unwrap();

    handle_encrypted_negative_report(&db, valid_report_1.encrypt(&public));
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    let negative_reports = nrs_to_process.get(&map_key_1).unwrap();
    assert_eq!(negative_reports.len(), 1);

    handle_encrypted_negative_report(&db, invalid_report_1.encrypt(&public)); // no change
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    let negative_reports = nrs_to_process.get(&map_key_1).unwrap();
    assert_eq!(negative_reports.len(), 1);

    let map_key_2 = format!(
        "{}_{}_{}",
        array_bytes::bytes2hex("", invalid_report_2.fingerprint),
        "ru".to_string(),
        date
    );
    handle_encrypted_negative_report(&db, invalid_report_2.encrypt(&public)); // no change
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    assert!(!nrs_to_process.contains_key(&map_key_2));

    let map_key_3 = format!(
        "{}_{}_{}",
        array_bytes::bytes2hex("", valid_report_2.fingerprint),
        "ru".to_string(),
        date - 1
    );
    handle_encrypted_negative_report(&db, valid_report_2.encrypt(&public_yesterday));
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    let negative_reports = nrs_to_process.get(&map_key_3).unwrap();
    assert_eq!(negative_reports.len(), 1);

    handle_encrypted_negative_report(&db, valid_report_3.encrypt(&public));
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    let negative_reports = nrs_to_process.get(&map_key_1).unwrap();
    assert_eq!(negative_reports.len(), 2);

    // Same tests, but use hash of bucket

    // Delete all data in test DB
    db.clear().unwrap();
    assert!(!db.contains_key("nrs-to-process").unwrap());

    // Re-generate keys and save in database
    let public = new_negative_report_key(&db, date).unwrap();
    let public_yesterday = new_negative_report_key(&db, date - 1).unwrap();

    let mut nonce = [0; 32];
    rng.fill_bytes(&mut nonce);

    // A valid report
    let valid_report_1 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBucket(HashOfBucket::new(&cred.bucket, date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    // Report which reuses this nonce
    let invalid_report_1 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBucket(HashOfBucket::new(&cred.bucket, date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    // This is the same report
    assert_eq!(valid_report_1, invalid_report_1);

    // Report which reuses this nonce for a different bridge
    let invalid_report_2 = NegativeReport::new(
        bridges[1].fingerprint,
        ProofOfBridgeKnowledge::HashOfBucket(HashOfBucket::new(&cred.bucket, date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    // Report which uses this nonce but on a different day
    let valid_report_2 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBucket(HashOfBucket::new(&cred.bucket, date - 1, nonce)),
        "ru".to_string(),
        date - 1,
        nonce,
        BridgeDistributor::Lox,
    );

    // Report with different nonce
    let mut nonce = [0; 32];
    rng.fill_bytes(&mut nonce);

    let valid_report_3 = NegativeReport::new(
        bridges[0].fingerprint,
        ProofOfBridgeKnowledge::HashOfBucket(HashOfBucket::new(&cred.bucket, date, nonce)),
        "ru".to_string(),
        date,
        nonce,
        BridgeDistributor::Lox,
    );

    let map_key_1 = format!(
        "{}_{}_{}",
        array_bytes::bytes2hex("", valid_report_1.fingerprint),
        "ru".to_string(),
        date
    );
    handle_encrypted_negative_report(&db, valid_report_1.encrypt(&public));
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    let negative_reports = nrs_to_process.get(&map_key_1).unwrap();
    assert_eq!(negative_reports.len(), 1);

    handle_encrypted_negative_report(&db, invalid_report_1.encrypt(&public)); // no change
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    let negative_reports = nrs_to_process.get(&map_key_1).unwrap();
    assert_eq!(negative_reports.len(), 1);

    let map_key_2 = format!(
        "{}_{}_{}",
        array_bytes::bytes2hex("", invalid_report_2.fingerprint),
        "ru".to_string(),
        date
    );
    handle_encrypted_negative_report(&db, invalid_report_2.encrypt(&public)); // no change
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    assert!(!nrs_to_process.contains_key(&map_key_2));

    let map_key_3 = format!(
        "{}_{}_{}",
        array_bytes::bytes2hex("", valid_report_2.fingerprint),
        "ru".to_string(),
        date - 1
    );
    handle_encrypted_negative_report(&db, valid_report_2.encrypt(&public_yesterday));
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    let negative_reports = nrs_to_process.get(&map_key_3).unwrap();
    assert_eq!(negative_reports.len(), 1);

    handle_encrypted_negative_report(&db, valid_report_3.encrypt(&public));
    let nrs_to_process: BTreeMap<String, Vec<SerializableNegativeReport>> =
        bincode::deserialize(&db.get("nrs-to-process").unwrap().unwrap()).unwrap();
    let negative_reports = nrs_to_process.get(&map_key_1).unwrap();
    assert_eq!(negative_reports.len(), 2);
}

#[test]
fn test_positive_reports() {
    let mut th = TestHarness::new();

    // Get new level 3 credential
    let cred = th.get_new_credential();
    let cred = th.level_up(&cred);
    let cred = th.level_up(&cred);
    let cred = th.level_up(&cred);

    let bridges = th.get_bucket(&cred);

    // Create BridgeVerificationInfo for each bridge
    let mut buckets = HashSet::<Scalar>::new();
    buckets.insert(cred.bucket);
    let bridge_info_1 = BridgeVerificationInfo {
        bridge_line: bridges[0],
        buckets: buckets.clone(),
        pubkey: None,
    };
    let bridge_info_2 = BridgeVerificationInfo {
        bridge_line: bridges[1],
        buckets: buckets.clone(),
        pubkey: None,
    };
    let bridge_info_3 = BridgeVerificationInfo {
        bridge_line: bridges[2],
        buckets: buckets.clone(),
        pubkey: None,
    };

    // Create reports
    let report_1 = PositiveReport::from_lox_credential(
        bridges[0].fingerprint,
        None,
        &cred,
        &th.ba.lox_pub,
        "ru".to_string(),
    )
    .unwrap();
    let report_2 = PositiveReport::from_lox_credential(
        bridges[1].fingerprint,
        None,
        &cred,
        &th.ba.lox_pub,
        "ru".to_string(),
    )
    .unwrap();
    let report_3 = PositiveReport::from_lox_credential(
        bridges[2].fingerprint,
        None,
        &cred,
        &th.ba.lox_pub,
        "ru".to_string(),
    )
    .unwrap();

    // Compute Htable
    let H = lox_library::proto::positive_report::compute_H(report_1.date);
    let Htable = RistrettoBasepointTable::create(&H);

    assert!(report_1.verify(&mut th.ba, &bridge_info_1, &Htable));
    assert!(report_2.verify(&mut th.ba, &bridge_info_2, &Htable));
    assert!(report_3.verify(&mut th.ba, &bridge_info_3, &Htable));

    // Check that user cannot use credential for other bridge

    // Get new credential
    let cred_2 = th.get_new_credential();
    let bridges_2 = th.get_bucket(&cred_2);

    let mut buckets_2 = HashSet::<Scalar>::new();
    buckets_2.insert(cred_2.bucket);
    let bridge_info_4 = BridgeVerificationInfo {
        bridge_line: bridges_2[0],
        buckets: buckets_2.clone(),
        pubkey: None,
    };

    // Use new credential to create positive report even we don't trust it
    let invalid_report_1 = PositiveReport::from_lox_credential(
        bridges_2[0].fingerprint,
        None,
        &cred_2,
        &th.ba.lox_pub,
        "ru".to_string(),
    );

    // Use first credential for bridge from second bucket
    let invalid_report_2 = PositiveReport::from_lox_credential(
        bridges_2[0].fingerprint,
        None,
        &cred,
        &th.ba.lox_pub,
        "ru".to_string(),
    );

    // Use second credential for bridge from first bucket
    let invalid_report_3 = PositiveReport::from_lox_credential(
        bridges[0].fingerprint,
        None,
        &cred_2,
        &th.ba.lox_pub,
        "ru".to_string(),
    );

    // Check that all of these fail
    assert!(invalid_report_1.is_err());
    assert!(!invalid_report_2
        .unwrap()
        .verify(&mut th.ba, &bridge_info_4, &Htable));
    assert!(invalid_report_3.is_err());

    // Check that deserialization fails under invalid conditions

    // Date in the future
    let mut invalid_report_4 = PositiveReport::from_lox_credential(
        bridges[0].fingerprint,
        None,
        &cred,
        &th.ba.lox_pub,
        "ru".to_string(),
    )
    .unwrap()
    .to_serializable_report();
    invalid_report_4.date = invalid_report_4.date + 2;

    // Invalid country code
    let invalid_report_5 = PositiveReport::from_lox_credential(
        bridges[0].fingerprint,
        None,
        &cred,
        &th.ba.lox_pub,
        "xx".to_string(),
    )
    .unwrap()
    .to_serializable_report();

    assert!(invalid_report_4.to_report().is_err());
    assert!(invalid_report_5.to_report().is_err());

    // Test storing to-be-processed positive reports to database

    // Create reports
    let report_1 = PositiveReport::from_lox_credential(
        bridges[0].fingerprint,
        None,
        &cred,
        &th.ba.lox_pub,
        "ru".to_string(),
    )
    .unwrap();
    let report_2 = PositiveReport::from_lox_credential(
        bridges[0].fingerprint,
        None,
        &cred,
        &th.ba.lox_pub,
        "ru".to_string(),
    )
    .unwrap();
    let report_3 = PositiveReport::from_lox_credential(
        bridges[1].fingerprint,
        None,
        &cred,
        &th.ba.lox_pub,
        "ru".to_string(),
    )
    .unwrap();

    // Open test database
    let db: Db = sled::open("test_db_pr").unwrap();

    // Delete all data in test DB
    db.clear().unwrap();
    assert!(!db.contains_key("prs-to-process").unwrap());

    let map_key_1 = format!(
        "{}_{}_{}",
        array_bytes::bytes2hex("", report_1.fingerprint),
        &report_1.country,
        &report_1.date
    );
    let map_key_2 = format!(
        "{}_{}_{}",
        array_bytes::bytes2hex("", report_3.fingerprint),
        &report_3.country,
        &report_3.date
    );

    save_positive_report_to_process(&db, report_1);
    let prs_to_process: BTreeMap<String, Vec<SerializablePositiveReport>> =
        bincode::deserialize(&db.get("prs-to-process").unwrap().unwrap()).unwrap();
    let positive_reports = prs_to_process.get(&map_key_1).unwrap();
    assert_eq!(positive_reports.len(), 1);
    assert!(!prs_to_process.contains_key(&map_key_2));

    save_positive_report_to_process(&db, report_2);
    let prs_to_process: BTreeMap<String, Vec<SerializablePositiveReport>> =
        bincode::deserialize(&db.get("prs-to-process").unwrap().unwrap()).unwrap();
    let positive_reports = prs_to_process.get(&map_key_1).unwrap();
    assert_eq!(positive_reports.len(), 2);
    assert!(!prs_to_process.contains_key(&map_key_2));

    save_positive_report_to_process(&db, report_3);
    let prs_to_process: BTreeMap<String, Vec<SerializablePositiveReport>> =
        bincode::deserialize(&db.get("prs-to-process").unwrap().unwrap()).unwrap();
    // Check that this has not changed
    let positive_reports = prs_to_process.get(&map_key_1).unwrap();
    assert_eq!(positive_reports.len(), 2);
    // New report added to its own collection
    let positive_reports = prs_to_process.get(&map_key_2).unwrap();
    assert_eq!(positive_reports.len(), 1);
}

#[test]
fn test_analysis() {
    // Test stage 1 analysis
    {
        let mut date = get_date();

        // New bridge info
        let mut bridge_info = BridgeInfo::new([0; 20], &String::default());

        bridge_info
            .info_by_country
            .insert("ru".to_string(), BridgeCountryInfo::new(date));
        let analyzer = analysis::NormalAnalyzer::new(5, 0.25);
        let confidence = 0.95;

        let mut blocking_countries = HashSet::<String>::new();

        // No data today
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // 1 connection, 0 negative reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            8,
        );
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // 0 connections, 0 negative reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            0,
        );
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // 0 connections, 1 negative report
        // (exceeds scaled threshold)
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            1,
        );
        blocking_countries.insert("ru".to_string());
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );
    }

    {
        let mut date = get_date();

        // New bridge info
        let mut bridge_info = BridgeInfo::new([0; 20], &String::default());

        bridge_info
            .info_by_country
            .insert("ru".to_string(), BridgeCountryInfo::new(date));
        let analyzer = analysis::NormalAnalyzer::new(5, 0.25);
        let confidence = 0.95;

        let mut blocking_countries = HashSet::<String>::new();

        // No data today
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // 1 connection, 1 negative report
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            8,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            1,
        );
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // 8 connections, 2 negative reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            8,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            2,
        );
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // 8 connections, 3 negative reports
        // (exceeds scaled threshold)
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            8,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            3,
        );
        blocking_countries.insert("ru".to_string());
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );
    }

    {
        let mut date = get_date();

        // New bridge info
        let mut bridge_info = BridgeInfo::new([0; 20], &String::default());

        bridge_info
            .info_by_country
            .insert("ru".to_string(), BridgeCountryInfo::new(date));
        let analyzer = analysis::NormalAnalyzer::new(5, 0.25);
        let confidence = 0.95;

        let mut blocking_countries = HashSet::<String>::new();

        // 24 connections, 5 negative reports
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            24,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            5,
        );
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // 24 connections, 6 negative reports
        // (exceeds max threshold)
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            24,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            6,
        );
        blocking_countries.insert("ru".to_string());
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );
    }

    // Test stage 2 analysis

    {
        let mut date = get_date();

        // New bridge info
        let mut bridge_info = BridgeInfo::new([0; 20], &String::default());

        bridge_info
            .info_by_country
            .insert("ru".to_string(), BridgeCountryInfo::new(date));
        let analyzer = analysis::NormalAnalyzer::new(5, 0.25);
        let confidence = 0.95;

        let mut blocking_countries = HashSet::<String>::new();

        // No data today
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        for i in 1..30 {
            // 9-32 connections, 0-3 negative reports each day
            date += 1;
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::BridgeIps,
                date,
                8 * (i % 3 + 2),
            );
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::NegativeReports,
                date,
                i % 4,
            );
            assert_eq!(
                blocked_in(&analyzer, &bridge_info, confidence, date),
                blocking_countries
            );
        }

        // Data similar to previous days:
        // 24 connections, 2 negative reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            24,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            2,
        );

        // Should not be blocked because we have similar data.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 104 connections, 1 negative report
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            104,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            1,
        );

        // This should not be blocked even though it's very different because
        // it's different in the good direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 40 connections, 12 negative reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            40,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            12,
        );
        blocking_countries.insert("ru".to_string());

        // This should be blocked because it's different in the bad direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );
    }

    {
        let mut date = get_date();

        // New bridge info
        let mut bridge_info = BridgeInfo::new([0; 20], &String::default());

        bridge_info
            .info_by_country
            .insert("ru".to_string(), BridgeCountryInfo::new(date));
        let analyzer = analysis::NormalAnalyzer::new(5, 0.25);
        let confidence = 0.95;

        let mut blocking_countries = HashSet::<String>::new();

        // No data today
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        for i in 1..30 {
            // 9-32 connections, 0-3 negative reports each day
            date += 1;
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::BridgeIps,
                date,
                8 * (i % 3 + 2),
            );
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::NegativeReports,
                date,
                i % 4,
            );
            assert_eq!(
                blocked_in(&analyzer, &bridge_info, confidence, date),
                blocking_countries
            );
        }

        // Data similar to previous days:
        // 24 connections, 2 negative reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            24,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            2,
        );

        // Should not be blocked because we have similar data.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 104 connections, 1 negative report
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            104,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            1,
        );

        // This should not be blocked even though it's very different because
        // it's different in the good direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 800 connections, 12 negative reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            800,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            12,
        );
        blocking_countries.insert("ru".to_string());

        // The censor artificially inflated bridge stats to prevent detection.
        // Ensure we still detect the censorship from negative reports.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );
    }

    {
        let mut date = get_date();

        // New bridge info
        let mut bridge_info = BridgeInfo::new([0; 20], &String::default());

        bridge_info
            .info_by_country
            .insert("ru".to_string(), BridgeCountryInfo::new(date));
        let analyzer = analysis::NormalAnalyzer::new(5, 0.25);
        let confidence = 0.95;

        let mut blocking_countries = HashSet::<String>::new();

        // No data today
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        for i in 1..30 {
            // 9-32 connections, 0-3 negative reports each day
            date += 1;
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::BridgeIps,
                date,
                8 * (i % 3 + 2),
            );
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::NegativeReports,
                date,
                i % 4,
            );
            assert_eq!(
                blocked_in(&analyzer, &bridge_info, confidence, date),
                blocking_countries
            );
        }

        // Data similar to previous days:
        // 24 connections, 2 negative reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            24,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            2,
        );

        // Should not be blocked because we have similar data.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 104 connections, 1 negative report
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            104,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            1,
        );

        // This should not be blocked even though it's very different because
        // it's different in the good direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 0 connections, 0 negative reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            0,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            0,
        );
        blocking_countries.insert("ru".to_string());

        // This should be blocked because it's different in the bad direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );
    }

    // Test stage 3 analysis

    {
        let mut date = get_date();

        // New bridge info
        let mut bridge_info = BridgeInfo::new([0; 20], &String::default());

        bridge_info
            .info_by_country
            .insert("ru".to_string(), BridgeCountryInfo::new(date));
        let analyzer = analysis::NormalAnalyzer::new(5, 0.25);
        let confidence = 0.95;

        let mut blocking_countries = HashSet::<String>::new();

        // No data today
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        for i in 1..30 {
            // 9-32 connections, 0-3 negative reports, 16-20 positive reports each day
            date += 1;
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::BridgeIps,
                date,
                8 * (i % 3 + 2),
            );
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::NegativeReports,
                date,
                i % 4,
            );
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::PositiveReports,
                date,
                16 + i % 5,
            );
            assert_eq!(
                blocked_in(&analyzer, &bridge_info, confidence, date),
                blocking_countries
            );
        }

        // Data similar to previous days:
        // 24 connections, 2 negative reports, 17 positive reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            24,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            2,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::PositiveReports,
            date,
            17,
        );

        // Should not be blocked because we have similar data.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 104 connections, 1 negative report, 100 positive reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            104,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            1,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::PositiveReports,
            date,
            100,
        );

        // This should not be blocked even though it's very different because
        // it's different in the good direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 40 connections, 12 negative reports, 40 positive reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            40,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            12,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::PositiveReports,
            date,
            40,
        );
        blocking_countries.insert("ru".to_string());

        // This should be blocked because it's different in the bad direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );
    }

    {
        let mut date = get_date();

        // New bridge info
        let mut bridge_info = BridgeInfo::new([0; 20], &String::default());

        bridge_info
            .info_by_country
            .insert("ru".to_string(), BridgeCountryInfo::new(date));
        let analyzer = analysis::NormalAnalyzer::new(5, 0.25);
        let confidence = 0.95;

        let mut blocking_countries = HashSet::<String>::new();

        // No data today
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        for i in 1..30 {
            // 9-32 connections, 0-3 negative reports, 16-20 positive reports each day
            date += 1;
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::BridgeIps,
                date,
                8 * (i % 3 + 2),
            );
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::NegativeReports,
                date,
                i % 4,
            );
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::PositiveReports,
                date,
                16 + i % 5,
            );
            assert_eq!(
                blocked_in(&analyzer, &bridge_info, confidence, date),
                blocking_countries
            );
        }

        // Data similar to previous days:
        // 24 connections, 2 negative reports, 17 positive reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            24,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            2,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::PositiveReports,
            date,
            17,
        );

        // Should not be blocked because we have similar data.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 104 connections, 1 negative report, 85 positive reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            104,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            1,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::PositiveReports,
            date,
            85,
        );

        // This should not be blocked even though it's very different because
        // it's different in the good direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 800 connections, 12 negative reports, 750 positive reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            800,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            12,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::PositiveReports,
            date,
            750,
        );

        blocking_countries.insert("ru".to_string());

        // The censor artificially inflated bridge stats to prevent detection.
        // Ensure we still detect the censorship from negative reports.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );
    }

    {
        let mut date = get_date();

        // New bridge info
        let mut bridge_info = BridgeInfo::new([0; 20], &String::default());

        bridge_info
            .info_by_country
            .insert("ru".to_string(), BridgeCountryInfo::new(date));
        let analyzer = analysis::NormalAnalyzer::new(5, 0.25);
        let confidence = 0.95;

        let mut blocking_countries = HashSet::<String>::new();

        // No data today
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        for i in 1..30 {
            // 9-32 connections, 0-3 negative reports, 16-20 positive reports each day
            date += 1;
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::BridgeIps,
                date,
                8 * (i % 3 + 2),
            );
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::NegativeReports,
                date,
                i % 4,
            );
            bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
                BridgeInfoType::PositiveReports,
                date,
                16 + i % 5,
            );
            assert_eq!(
                blocked_in(&analyzer, &bridge_info, confidence, date),
                blocking_countries
            );
        }

        // Data similar to previous days:
        // 24 connections, 2 negative reports, 17 positive reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            24,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            2,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::PositiveReports,
            date,
            17,
        );

        // Should not be blocked because we have similar data.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 104 connections, 1 negative report, 100 positive reports
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            104,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            1,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::PositiveReports,
            date,
            100,
        );

        // This should not be blocked even though it's very different because
        // it's different in the good direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );

        // Data different from previous days:
        // 24 connections, 1 negative report, 1 positive report
        date += 1;
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::BridgeIps,
            date,
            24,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::NegativeReports,
            date,
            1,
        );
        bridge_info.info_by_country.get_mut("ru").unwrap().add_info(
            BridgeInfoType::PositiveReports,
            date,
            1,
        );

        blocking_countries.insert("ru".to_string());

        // This should be blocked because it's different in the bad direction.
        assert_eq!(
            blocked_in(&analyzer, &bridge_info, confidence, date),
            blocking_countries
        );
    }
}