diff --git a/test/coin-test.js b/test/coin-test.js
index c6e25a8ff..857bd17ef 100644
--- a/test/coin-test.js
+++ b/test/coin-test.js
@@ -48,4 +48,34 @@ describe('Coin', function() {
     assert(fmt.includes('coinbase'));
     assert(fmt.includes('script'));
   });
+
+  it('should throw error for invalid input raw data', () => {
+    let error;
+    try {
+      Coin.fromRaw(Buffer.from([]));
+    } catch (e) {
+      error = e;
+    }
+
+    assert(error instanceof Error);
+    assert.strictEqual(error.message, 'Out of bounds read (offset=0).');
+  });
+
+  it('should return expected txid', () => {
+    const [tx] = tx1.getTX();
+    const coin = Coin.fromTX(tx, 0, 0);
+    assert.strictEqual(coin.txid(), 'ff80fe4937e2de16411c3a2bc534d661dc8b4f8aad75e6fbc4b1ec6060d9ef1c');
+  });
+
+  it('should return expected type', () => {
+    const [tx] = tx1.getTX();
+    const coin = Coin.fromTX(tx, 0, 0);
+    assert.strictEqual(coin.getType(), 'multisig');
+  });
+
+  it('should return expected address', () => {
+    const [tx] = tx1.getTX();
+    const coin = Coin.fromTX(tx, 0, 0);
+    assert.strictEqual(coin.getAddress().toString(), '3KUER9kZ693d5FQgvmr5qNDKnSpP9nXv9v');
+  });
 });
diff --git a/test/coins-test.js b/test/coins-test.js
index 7e3f48dbe..0c2737021 100644
--- a/test/coins-test.js
+++ b/test/coins-test.js
@@ -99,4 +99,32 @@ describe('Coins', function() {
     assert.strictEqual(coins.get(0), null);
     deepCoinsEqual(coins.get(1), reserialize(coins.get(1)));
   });
+
+  it('should spend multiple outputs from a single transaction', () => {
+    const [tx, view] = tx1.getTX();
+
+    view.addTX(tx, 1);
+
+    const hash = tx.hash();
+    const coins = view.get(hash);
+
+    view.spendEntry(new Outpoint(hash, 0));
+    view.spendEntry(new Outpoint(hash, 1));
+
+    assert.strictEqual(coins.get(0).spent, true);
+    assert.strictEqual(coins.get(1).spent, true);
+    assert.strictEqual(view.undo.items.length, 2);
+  });
+
+  it('should handle serialization and deserialization of the coin view', () => {
+    const [tx, view] = tx1.getTX();
+
+    const size = view.getSize(tx);
+    const bw = bio.write(size);
+    const raw = view.toWriter(bw, tx).render();
+    const br = bio.read(raw);
+    const res = CoinView.fromReader(br, tx);
+
+    assert.deepStrictEqual(view, res);
+  });
 });
diff --git a/test/consensus-test.js b/test/consensus-test.js
index 03503d442..f92c4739d 100644
--- a/test/consensus-test.js
+++ b/test/consensus-test.js
@@ -64,4 +64,90 @@ describe('Consensus', function() {
     assert(consensus.hasBit(0x20000003, 1));
     assert(consensus.hasBit(0x20000003, 0));
   });
+
+  it('should calculate block reward properly', () => {
+    let height = 0;
+    const reward = consensus.getReward(height, 210000);
+    assert.strictEqual(reward, 50 * consensus.COIN);
+    height = 210000;
+    const reward2 = consensus.getReward(height, 210000);
+    assert.strictEqual(reward2, 25 * consensus.COIN);
+  });
+
+  it('should throw an error for invalid height', () => {
+    assert.throws(() => {
+    consensus.getReward(-100, 210000);
+    }, /Bad height for reward./);
+  });
+
+  it('should return false for invalid proof-of-work', () => {
+    const bits = 0x1900896c;
+    const hash = Buffer.from(
+    '672b3f1bb11a994267ea4171069ba0aa4448a840f38e8f340000000000000001',
+    'hex');
+    assert.strictEqual(consensus.verifyPOW(hash, bits), false);
+  });
+
+  it('should return correct reward amount at given height and reward interval', () => {
+    const height = 210000;
+    const rewardInterval = 210000;
+    const expectedReward = 25 * consensus.COIN;
+
+    const reward = consensus.getReward(height, rewardInterval);
+
+    assert.strictEqual(reward, expectedReward);
+  });
+
+  it('should correctly determine whether a given version number contains a specific bit', () => {
+    const version = 0x20000001;
+    const bit = 0;
+    const expectedResult = true;
+
+    const result = consensus.hasBit(version, bit);
+
+    assert.strictEqual(result, expectedResult);
+  });
+
+  it('should correctly convert target to compact representation of target', () => {
+    const target = new BN(
+      '0000000000000000896c00000000000000000000000000000000000000000000',
+      'hex');
+    const expectedCompact = 0x1900896c;
+
+    const compact = consensus.toCompact(target);
+
+    assert.strictEqual(compact, expectedCompact);
+  });
+
+  it('should correctly verify proof of work', () => {
+    const hash = Buffer.from(
+      '672b3f1bb11a994267ea4171069ba0aa4448a840f38e8f340000000000000000',
+      'hex'
+    );
+    const bits = 0x1900896c;
+    const expectedResult = true;
+
+    const result = consensus.verifyPOW(hash, bits);
+
+    assert.strictEqual(result, expectedResult);
+  });
+
+  it('should correctly return total reward for all blocks until the reward becomes zero', () => {
+    let height = 0;
+    let total = 0;
+
+    for (;;) {
+      const reward = consensus.getReward(height, 210000);
+      total += reward;
+      if (reward === 0)
+        break;
+      height++;
+    }
+
+    const expectedHeight = 6930000;
+    const expectedTotal = 2099999997690000;
+
+    assert.strictEqual(height, expectedHeight);
+    assert.strictEqual(total, expectedTotal);
+  });
 });
diff --git a/test/gcs-test.js b/test/gcs-test.js
index f3f566671..1bf6697c0 100644
--- a/test/gcs-test.js
+++ b/test/gcs-test.js
@@ -170,4 +170,14 @@ describe('GCS', function () {
     match = filter2.matchAny(key, contents);
     assert(match);
   });
+
+  it('should test toBytes', () => {
+    const filterBytes = filter1.toBytes();
+    assert(filterBytes instanceof Buffer);
+  });
+
+  it('should test toNBytes', () => {
+    const filterNBytes = filter1.toNBytes();
+    assert(filterNBytes instanceof Buffer);
+  });
 });
diff --git a/test/headers-test.js b/test/headers-test.js
index 338283bf0..7ebf4130a 100644
--- a/test/headers-test.js
+++ b/test/headers-test.js
@@ -55,4 +55,20 @@ describe('Headers', function() {
     assert(headers.verifyBody());
     assert(headers.verifyPOW());
   });
+
+  it('should match raw headers from headers', () => {
+    const headers = new Headers();
+    headers.time = 1231469665;
+    headers.bits = 486604799;
+    headers.nonce = 2573394689;
+    headers.version = 1;
+    headers.prevBlock = Buffer.from(
+      '6fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d6190000000000',
+      'hex');
+    headers.merkleRoot = Buffer.from(
+      '982051fd1e4ba744bbbe680e1fee14677ba1a3c3540bf7b1cdb606e857233e0e',
+      'hex');
+
+    assert.bufferEqual(headers.toRaw(), headers1);
+  });
 });
diff --git a/test/mnemonic-test.js b/test/mnemonic-test.js
index b0e670df1..1e3b6134a 100644
--- a/test/mnemonic-test.js
+++ b/test/mnemonic-test.js
@@ -64,4 +64,22 @@ describe('Mnemonic', function() {
     assert.strictEqual(m2.language, m1.language);
     assert.bufferEqual(m2.toSeed(), m1.toSeed());
   });
+
+  it('should create different seed with different passphrase', () => {
+    const mnemonic = new Mnemonic();
+    const seed1 = mnemonic.toSeed();
+    const seed2 = mnemonic.toSeed('different passphrase');
+    assert.notDeepEqual(seed1, seed2);
+  });
+
+  it('should create a mnemonic in French', () => {
+    const mnemonic = new Mnemonic({language: 'french'});
+    assert.strictEqual(mnemonic.language, 'french');
+  });
+
+  it('should create an HD Private Key from a mnemonic with no passphrase', () => {
+    const mnemonic = new Mnemonic();
+    const key = HDPrivateKey.fromMnemonic(mnemonic);
+    assert.strictEqual(key.depth, 0);
+  });
 });
diff --git a/test/mtx-test.js b/test/mtx-test.js
index 7b885012c..965df40b5 100644
--- a/test/mtx-test.js
+++ b/test/mtx-test.js
@@ -40,4 +40,54 @@ describe('MTX', function () {
     const mtx2 = MTX.fromRaw(mtx1.toRaw());
     assert.deepStrictEqual(mtx1, mtx2);
   });
+
+  it('should encode and decode mtx with multiple inputs and outputs', () => {
+    const input1 = new Input({
+      prevout: {
+        hash: Buffer.alloc(32),
+        index: 0
+      }
+    });
+    const input2 = new Input({
+      prevout: {
+        hash: Buffer.alloc(32),
+        index: 1
+      }
+    });
+    const output1 = new Output({
+      value: 1e8,
+      address: new Address()
+    });
+    const output2 = new Output({
+      value: 2e8,
+      address: new Address()
+    });
+    const mtx1 = new MTX({
+      inputs: [input1, input2],
+      outputs: [output1, output2]
+    });
+    const mtx2 = MTX.fromRaw(mtx1.toRaw());
+    assert.deepStrictEqual(mtx1, mtx2);
+  });
+
+  it('should encode and decode mtx with segwit inputs and outputs', () => {
+    const input = new Input({
+      prevout: {
+        hash: Buffer.alloc(32),
+        index: 0
+      },
+      witness: [Buffer.alloc(4)]
+    });
+    const output = new Output({
+      value: 1e8,
+      address: new Address(),
+      script: Buffer.alloc(4)
+    });
+    const mtx1 = new MTX({
+      inputs: [input],
+      outputs: [output]
+    });
+    const mtx2 = MTX.fromRaw(mtx1.toRaw());
+    assert.deepStrictEqual(mtx1, mtx2);
+  });
 });
diff --git a/test/pow-test.js b/test/pow-test.js
index 5c780cf2e..51c02ded8 100644
--- a/test/pow-test.js
+++ b/test/pow-test.js
@@ -72,6 +72,27 @@ describe('Difficulty', function() {
     assert.strictEqual(chain.retarget(prev, first), 0x1d00e1fd);
   });
 
+  it('should test retarget with a range of inputs', async () => {
+    // Create an array of test cases
+    const testCases = [
+        { prevTime: 1262152739, prevBits: 0x1d00ffff, firstTime: 1261130161, expected: 0x1d00d86a },
+        { prevTime: 1233061996, prevBits: 0x1d00ffff, firstTime: 1231006505, expected: 0x1d00ffff },
+        { prevTime: 1279297671, prevBits: 0x1c05a3f4, firstTime: 1279008237, expected: 0x1c0168fd },
+        { prevTime: 1269211443, prevBits: 0x1c387f6f, firstTime: 1263163443, expected: 0x1d00e1fd }
+    ];
+
+    // Iterate through the test cases and check the output of the retarget function
+    for (const testCase of testCases) {
+        const prev = new ChainEntry();
+        prev.time = testCase.prevTime;
+        prev.bits = testCase.prevBits;
+        prev.height = 32255;
+        const first = new ChainEntry();
+        first.time = testCase.firstTime;
+        assert.strictEqual(chain.retarget(prev, first), testCase.expected);
+    }
+  });
+
   it('should get block proof equivalent time', async () => {
     const blocks = [];
     for (let i = 0; i < 10000; i++) {