v6 initial commit, maybe more to follow

blockchain/block.test.js

@@ -0,0 +1,34 @@
+const Block = require('./block');
+
+describe('Block', () => {
+  let data, lastBlock, block;
+
+  beforeEach(() => {
+    data = 'bar';
+    lastBlock = Block.genesis();
+    block = Block.mineBlock(lastBlock, data);
+  });
+
+  it('sets the `data` to match the input', () => {
+    expect(block.data).toEqual(data);
+  });
+
+  it('sets the `lastHash` to match the hash of the last block', () => {
+    expect(block.lastHash).toEqual(lastBlock.hash);
+  });
+
+  it('generates a hash that matches the difficulty', () => {
+    expect(block.hash.substring(0, block.difficulty))
+      .toEqual('0'.repeat(block.difficulty));
+  });
+
+  it('lowers the difficulty for slowly mined blocks', () => {
+    expect(Block.adjustDifficulty(block, block.timestamp+360000))
+      .toEqual(block.difficulty-1);
+  });
+
+  it('raises the difficulty for quickly mined blocks', () => {
+    expect(Block.adjustDifficulty(block, block.timestamp+1))
+      .toEqual(block.difficulty+1);
+  });
+});