v6 initial commit, maybe more to follow

blockchain/index.test.js

@@ -0,0 +1,55 @@
+const Blockchain = require('./index');
+const Block = require('./block');
+
+describe('Blockchain', () => {
+  let bc, bc2;
+
+  beforeEach(() => {
+    bc = new Blockchain();
+    bc2 = new Blockchain();
+  });
+
+  it('starts with genesis block', () => {
+    expect(bc.chain[0]).toEqual(Block.genesis());
+  });
+
+  it('adds a new block', () => {
+    const data = 'foo';
+    bc.addBlock(data);
+
+    expect(bc.chain[bc.chain.length-1].data).toEqual(data);
+  });
+
+  it('validates a valid chain', () => {
+    bc2.addBlock('foo');
+
+    expect(bc.isValidChain(bc2.chain)).toBe(true);
+  });
+
+  it('invalidates a chain with a corrupt genesis block', () => {
+    bc2.chain[0].data = 'Bad data';
+
+    expect(bc.isValidChain(bc2.chain)).toBe(false);
+  });
+
+  it('invalidates a corrupt chain', () => {
+    bc2.addBlock('foo');
+    bc2.chain[1].data = 'Not foo';
+
+    expect(bc.isValidChain(bc2.chain)).toBe(false);
+  });
+
+  it('replaces the chain with a valid chain', () => {
+    bc2.addBlock('goo');
+    bc.replaceChain(bc2.chain);
+
+    expect(bc.chain).toEqual(bc2.chain);
+  });
+
+  it('does not replace the chain with one of less than or equal to length', () => {
+    bc.addBlock('foo');
+    bc.replaceChain(bc2.chain);
+
+    expect(bc.chain).not.toEqual(bc2.chain);
+  })
+});