[WIP] Add module for writing unit tests

modules.json

@@ -111,5 +111,10 @@
   },
   "communication": {
     "tabs": []
+  },
+  "testing": {
+    "tabs": [
+      "Testing"
+    ]
   }
 }

src/bundles/testing/__tests__/index.ts

@@ -0,0 +1,48 @@
+import * as asserts from '../asserts';
+import * as testing from '../functions';
+import { list } from '../list';
+
+beforeAll(() => {
+  testing.context.suiteResults = {
+    name: '',
+    results: [],
+    total: 0,
+    passed: 0,
+  };
+  testing.context.allResults.results = [];
+  testing.context.runtime = 0;
+});
+
+test('context is created correctly', () => {
+  const mockTestFn = jest.fn();
+  testing.describe('Testing 321', () => {
+    testing.it('Testing 123', mockTestFn);
+  });
+  expect(testing.context.suiteResults.passed).toEqual(1);
+  expect(mockTestFn).toHaveBeenCalled();
+});
+
+test('context fails correctly', () => {
+  testing.describe('Testing 123', () => {
+    testing.it('This test fails!', () => asserts.assert_equals(0, 1));
+  });
+  expect(testing.context.suiteResults.passed).toEqual(0);
+  expect(testing.context.suiteResults.total).toEqual(1);
+});
+
+test('assert works', () => {
+  expect(() => asserts.assert(() => true)).not.toThrow();
+  expect(() => asserts.assert(() => false)).toThrow('Assert failed');
+});
+
+test('assert_equals works', () => {
+  expect(() => asserts.assert_equals(1, 1)).not.toThrow();
+  expect(() => asserts.assert_equals(0, 1)).toThrow('Expected');
+  expect(() => asserts.assert_equals(1.00000000001, 1)).not.toThrow();
+});
+
+test('assert_contains works', () => {
+  const list1 = list(1, 2, 3);
+  expect(() => asserts.assert_contains(list1, 2)).not.toThrow();
+  expect(() => asserts.assert_contains(list1, 10)).toThrow();
+});

src/bundles/testing/asserts.ts

@@ -0,0 +1,85 @@
+import { is_pair, head, tail, is_list, is_null, member, length } from './list';
+
+/**
+ * Asserts that a predicate returns true.
+ * @param pred An predicate function that returns true/false.
+ * @returns
+ */
+export function assert(pred: () => boolean) {
+  if (!pred()) {
+    throw new Error('Assert failed!');
+  }
+}
+
+/**
+ * Asserts the equality (===) of two parameters.
+ * @param expected The expected value.
+ * @param received The given value.
+ * @returns
+ */
+export function assert_equals(expected: any, received: any) {
+  const fail = () => {
+    throw new Error(`Expected \`${expected}\`, got \`${received}\`!`);
+  };
+  if (typeof expected !== typeof received) {
+    fail();
+  }
+  // approx checking for floats
+  if (typeof expected === 'number' && !Number.isInteger(expected)) {
+    if (Math.abs(expected - received) > 0.001) {
+      fail();
+    } else {
+      return;
+    }
+  }
+  if (expected !== received) {
+    fail();
+  }
+}
+
+/**
+ * Asserts that `xs` contains `toContain`.
+ * @param xs The list to assert.
+ * @param toContain The element that `xs` is expected to contain.
+ */
+export function assert_contains(xs: any, toContain: any) {
+  const fail = () => {
+    throw new Error(`Expected \`${xs}\` to contain \`${toContain}\`.`);
+  };
+
+  if (is_null(xs)) {
+    fail();
+  } else if (is_list(xs)) {
+    if (is_null(member(toContain, xs))) {
+      fail();
+    }
+  } else if (is_pair(xs)) {
+    if (head(xs) === toContain || tail(xs) === toContain) {
+      return;
+    }
+
+    // check the head, if it fails, checks the tail, if that fails, fail.
+    try {
+      assert_contains(head(xs), toContain);
+      return;
+    } catch (_) {
+      try {
+        assert_contains(tail(xs), toContain);
+        return;
+      } catch (__) {
+        fail();
+      }
+    }
+  } else {
+    throw new Error(`First argument must be a list or a pair, got \`${xs}\`.`);
+  }
+}
+
+/**
+ * Asserts that the given list has length `len`.
+ * @param list The list to assert.
+ * @param len The expected length of the list.
+ */
+export function assert_length(list: any, len: number) {
+  assert_equals(length(list), len);
+}

src/bundles/testing/functions.ts

@@ -0,0 +1,82 @@
+import { TestContext, TestSuite, Test } from './types';
+
+const handleErr = (err: any) => {
+  if (err.error && err.error.message) {
+    return (err.error as Error).message;
+  }
+  if (err.message) {
+    return (err as Error).message;
+  }
+  throw err;
+};
+
+export const context: TestContext = {
+  describe: (msg: string, suite: TestSuite) => {
+    const starttime = performance.now();
+    context.suiteResults = {
+      name: msg,
+      results: [],
+      total: 0,
+      passed: 0,
+    };
+
+    suite();
+
+    context.allResults.results.push(context.suiteResults);
+
+    const endtime = performance.now();
+    context.runtime += endtime - starttime;
+    return context.allResults;
+  },
+
+  it: (msg: string, test: Test) => {
+    const name = `${msg}`;
+    let error = '';
+    context.suiteResults.total += 1;
+
+    try {
+      test();
+      context.suiteResults.passed += 1;
+    } catch (err: any) {
+      error = handleErr(err);
+    }
+
+    context.suiteResults.results.push({
+      name,
+      error,
+    });
+  },
+
+  suiteResults: {
+    name: '',
+    results: [],
+    total: 0,
+    passed: 0,
+  },
+
+  allResults: {
+    results: [],
+    toReplString: () =>
+      `${context.allResults.results.length} suites completed in ${context.runtime} ms.`,
+  },
+
+  runtime: 0,
+};
+
+/**
+ * Defines a single test.
+ * @param str Description for this test.
+ * @param func Function containing tests.
+ */
+export function it(msg: string, func: Test) {
+  context.it(msg, func);
+}
+
+/**
+ * Describes a test suite.
+ * @param str Description for this test.
+ * @param func Function containing tests.
+ */
+export function describe(msg: string, func: TestSuite) {
+  return context.describe(msg, func);
+}

src/bundles/testing/index.ts

@@ -0,0 +1,41 @@
+import {
+  assert_equals,
+  assert_not_equals,
+  assert_contains,
+  assert_approx_equals,
+  assert_greater,
+  assert_greater_equals,
+  assert_length,
+} from './asserts';
+import { it, describe } from './functions';
+import { mock_fn } from './mocks';
+
+/**
+ * Collection of unit-testing tools for Source.
+ * @author Jia Xiaodong
+ */
+
+/**
+ * Increment a number by a value of 1.
+ * @param x the number to be incremented
+ * @returns the incremented value of the number
+ */
+function sample_function(x: number) {
+  return x + 1;
+}
+
+// Un-comment the next line if your bundle requires the use of variables
+// declared in cadet-frontend or js-slang.
+export default () => ({
+  sample_function,
+  it,
+  describe,
+  assert_equals,
+  assert_not_equals,
+  assert_contains,
+  assert_greater,
+  assert_greater_equals,
+  assert_approx_equals,
+  assert_length,
+  mock_fn,
+});