test: add binarySerchCustom test (#36)

test/binary-search-custom.test.ts

@@ -0,0 +1,99 @@
+import { expect } from 'chai'
+import { assert, mock } from 'sinon'
+import { deepFreeze } from './helpers'
+
+import { binarySearchCustom } from '../src'
+
+describe('binarySearchCustom', function(): void {
+  const orderedItems = deepFreeze([
+    { prop1: -79, nested: { prop2: -0.79 } },
+    { prop1: -27, nested: { prop2: -0.27 } },
+    { prop1: -18, nested: { prop2: -0.18 } },
+    { prop1: -11, nested: { prop2: -0.11 } },
+    { prop1: 4, nested: { prop2: 0.4 } },
+    { prop1: 18, nested: { prop2: 0.18 } },
+    { prop1: 28, nested: { prop2: 0.28 } },
+    { prop1: 33, nested: { prop2: 0.33 } },
+    { prop1: 37, nested: { prop2: 0.37 } },
+    { prop1: 47, nested: { prop2: 0.47 } },
+    { prop1: 64, nested: { prop2: 0.64 } },
+    { prop1: 71, nested: { prop2: 0.71 } },
+    { prop1: 71, nested: { prop2: 0.71 } },
+    { prop1: 71, nested: { prop2: 0.71 } },
+    { prop1: 71, nested: { prop2: 0.71 } },
+    { prop1: 87, nested: { prop2: 0.87 } },
+  ])
+  const comparatorFactory = (target: number): ((value: number) => -1 | 0 | 1) => (value: number): -1 | 0 | 1 => {
+    if (value < target) {
+      return -1
+    } else if (value > target) {
+      return 1
+    } else {
+      return 0
+    }
+  }
+
+  describe('array[index][prop1]', function(): void {
+    it('comparator args', function(): void {
+      const bscMock = mock()
+      bscMock.returns(0)
+
+      binarySearchCustom(orderedItems, bscMock, 'prop1')
+
+      assert.calledOnce(bscMock)
+      expect(
+        bscMock.getCall(0).args,
+        'The comparator should receive the value retrieved from the array item using the passed property name.'
+      )
+        .to.have.lengthOf(1)
+        .and.to.have.ownProperty(0)
+        .that.is.a('number')
+    })
+
+    it('missing item', function(): void {
+      expect(binarySearchCustom(orderedItems, comparatorFactory(13), 'prop1')).to.equal(-1)
+    })
+
+    it('present item', function(): void {
+      expect(binarySearchCustom(orderedItems, comparatorFactory(28), 'prop1')).to.equal(6)
+    })
+
+    it('multiple equal items', function(): void {
+      expect(binarySearchCustom(orderedItems, comparatorFactory(71), 'prop1'))
+        .to.be.at.least(11)
+        .and.at.most(14)
+    })
+  })
+
+  describe('array[index][prop1][prop2]', function(): void {
+    it('comparator args', function(): void {
+      const bscMock = mock()
+      bscMock.returns(0)
+
+      binarySearchCustom(orderedItems, bscMock, 'nested', 'prop2')
+
+      assert.calledOnce(bscMock)
+      expect(
+        bscMock.getCall(0).args,
+        'The comparator should receive the value retrieved from the array item using the passed property names.'
+      )
+        .to.have.lengthOf(1)
+        .and.to.have.ownProperty(0)
+        .that.is.a('number')
+    })
+
+    it('missing item', function(): void {
+      expect(binarySearchCustom(orderedItems, comparatorFactory(0.13), 'nested', 'prop2')).to.equal(-1)
+    })
+
+    it('present item', function(): void {
+      expect(binarySearchCustom(orderedItems, comparatorFactory(0.28), 'nested', 'prop2')).to.equal(6)
+    })
+
+    it('multiple equal items', function(): void {
+      expect(binarySearchCustom(orderedItems, comparatorFactory(0.71), 'nested', 'prop2'))
+        .to.be.at.least(11)
+        .and.at.most(14)
+    })
+  })
+})