Refactor asserts in testing (denoland/deno_std#227)

Original: https://github.com/denoland/deno_std/commit/c734e3234322cea5298a887373fe4ad1591d7c97

7 files changed, 261 insertions, 140 deletions

diff --git a/testing/asserts.ts b/testing/asserts.ts
new file mode 100644
index 000000000..a2110b8d9
--- /dev/null
+++ b/testing/asserts.ts
@@ -0,0 +1,179 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { assertEqual as prettyAssertEqual } from "./pretty.ts";
+
+interface Constructor {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  new (...args: any[]): any;
+}
+
+/** Make an assertion, if not `true`, then throw. */
+export function assert(expr: boolean, msg = ""): void {
+  if (!expr) {
+    throw new Error(msg);
+  }
+}
+
+/**
+ * Make an assertion that `actual` and `expected` are equal, deeply. If not
+ * deeply equal, then throw.
+ */
+export function equal(actual: unknown, expected: unknown, msg?: string): void {
+  prettyAssertEqual(actual, expected, msg);
+}
+
+/**
+ * Make an assertion that `actual` and `expected` are strictly equal.  If
+ * not then throw.
+ */
+export function assertStrictEq(
+  actual: unknown,
+  expected: unknown,
+  msg?: string
+): void {
+  if (actual !== expected) {
+    let actualString: string;
+    let expectedString: string;
+    try {
+      actualString = String(actual);
+    } catch (e) {
+      actualString = "[Cannot display]";
+    }
+    try {
+      expectedString = String(expected);
+    } catch (e) {
+      expectedString = "[Cannot display]";
+    }
+    console.error(
+      "strictEqual failed. actual =",
+      actualString,
+      "expected =",
+      expectedString
+    );
+    if (!msg) {
+      msg = `actual: ${actualString} expected: ${expectedString}`;
+    }
+    throw new Error(msg);
+  }
+}
+
+/**
+ * Make an assertion that actual contains expected. If not
+ * then thrown.
+ */
+export function assertStrContains(
+  actual: string,
+  expected: string,
+  msg?: string
+): void {
+  if (!actual.includes(expected)) {
+    console.error(
+      "stringContains failed. actual =",
+      actual,
+      "not containing ",
+      expected
+    );
+    if (!msg) {
+      msg = `actual: "${actual}" expected to contains: "${expected}"`;
+    }
+    throw new Error(msg);
+  }
+}
+
+/**
+ * Make an assertion that `actual` match RegExp `expected`. If not
+ * then thrown
+ */
+export function assertMatch(
+  actual: string,
+  expected: RegExp,
+  msg?: string
+): void {
+  if (!expected.test(actual)) {
+    console.error(
+      "stringMatching failed. actual =",
+      actual,
+      "not matching RegExp ",
+      expected
+    );
+    if (!msg) {
+      msg = `actual: "${actual}" expected to match: "${expected}"`;
+    }
+    throw new Error(msg);
+  }
+}
+
+/**
+ * Forcefully throws a failed assertion
+ */
+export function fail(msg?: string): void {
+  // eslint-disable-next-line @typescript-eslint/no-use-before-define
+  assert(false, `Failed assertion${msg ? `: ${msg}` : "."}`);
+}
+
+/** Executes a function, expecting it to throw.  If it does not, then it
+ * throws.  An error class and a string that should be included in the
+ * error message can also be asserted.
+ */
+export function assertThrows(
+  fn: () => void,
+  ErrorClass?: Constructor,
+  msgIncludes = "",
+  msg?: string
+): void {
+  let doesThrow = false;
+  try {
+    fn();
+  } catch (e) {
+    if (ErrorClass && !(Object.getPrototypeOf(e) === ErrorClass.prototype)) {
+      msg = `Expected error to be instance of "${ErrorClass.name}"${
+        msg ? `: ${msg}` : "."
+      }`;
+      throw new Error(msg);
+    }
+    if (msgIncludes) {
+      if (!e.message.includes(msgIncludes)) {
+        msg = `Expected error message to include "${msgIncludes}", but got "${
+          e.message
+        }"${msg ? `: ${msg}` : "."}`;
+        throw new Error(msg);
+      }
+    }
+    doesThrow = true;
+  }
+  if (!doesThrow) {
+    msg = `Expected function to throw${msg ? `: ${msg}` : "."}`;
+    throw new Error(msg);
+  }
+}
+
+export async function assertThrowsAsync(
+  fn: () => Promise<void>,
+  ErrorClass?: Constructor,
+  msgIncludes = "",
+  msg?: string
+): Promise<void> {
+  let doesThrow = false;
+  try {
+    await fn();
+  } catch (e) {
+    if (ErrorClass && !(Object.getPrototypeOf(e) === ErrorClass.prototype)) {
+      msg = `Expected error to be instance of "${ErrorClass.name}"${
+        msg ? `: ${msg}` : "."
+      }`;
+      throw new Error(msg);
+    }
+    if (msgIncludes) {
+      if (!e.message.includes(msgIncludes)) {
+        msg = `Expected error message to include "${msgIncludes}", but got "${
+          e.message
+        }"${msg ? `: ${msg}` : "."}`;
+        throw new Error(msg);
+      }
+    }
+    doesThrow = true;
+  }
+  if (!doesThrow) {
+    msg = `Expected function to throw${msg ? `: ${msg}` : "."}`;
+    throw new Error(msg);
+  }
+}
diff --git a/testing/asserts_test.ts b/testing/asserts_test.ts
new file mode 100644
index 000000000..f4256d8f5
--- /dev/null
+++ b/testing/asserts_test.ts
@@ -0,0 +1,46 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+import { assertStrContains, assertMatch } from "./asserts.ts";
+import { test, assert } from "./mod.ts";
+// import { assertEqual as prettyAssertEqual } from "./pretty.ts";
+// import "./format_test.ts";
+// import "./diff_test.ts";
+// import "./pretty_test.ts";
+
+test(function testingAssertStringContains() {
+  assertStrContains("Denosaurus", "saur");
+  assertStrContains("Denosaurus", "Deno");
+  assertStrContains("Denosaurus", "rus");
+});
+
+test(function testingAssertStringContainsThrow() {
+  let didThrow = false;
+  try {
+    assertStrContains("Denosaurus from Jurassic", "Raptor");
+  } catch (e) {
+    assert(
+      e.message ===
+        `actual: "Denosaurus from Jurassic" expected to contains: "Raptor"`
+    );
+    didThrow = true;
+  }
+  assert(didThrow);
+});
+
+test(function testingAssertStringMatching() {
+  assertMatch("foobar@deno.com", RegExp(/[a-zA-Z]+@[a-zA-Z]+.com/));
+});
+
+test(function testingAssertStringMatchingThrows() {
+  let didThrow = false;
+  try {
+    assertMatch("Denosaurus from Jurassic", RegExp(/Raptor/));
+  } catch (e) {
+    assert(
+      e.message ===
+        `actual: "Denosaurus from Jurassic" expected to match: "/Raptor/"`
+    );
+    didThrow = true;
+  }
+  assert(didThrow);
+});
diff --git a/testing/bench.ts b/testing/bench.ts
index c5fd6b2a0..bc2e569d2 100644
--- a/testing/bench.ts
+++ b/testing/bench.ts
@@ -1,8 +1,6 @@
 import { bench, runBenchmarks } from "./../benching/mod.ts";
 import { runTests } from "./mod.ts";
 
-import "./test.ts";
-
 bench(async function testingSerial(b) {
   b.start();
   await runTests();
diff --git a/testing/diff.ts b/testing/diff.ts
index 4fab75e4a..e951032f5 100644
--- a/testing/diff.ts
+++ b/testing/diff.ts
@@ -4,7 +4,11 @@ interface FarthestPoint {
   id: number;
 }
 
-export type DiffType = "removed" | "common" | "added";
+export enum DiffType {
+  removed = "removed",
+  common = "common",
+  added = "added"
+}
 
 export interface DiffResult<T> {
   type: DiffType;
@@ -50,12 +54,12 @@ export default function diff<T>(A: T[], B: T[]): Array<DiffResult<T>> {
   if (!M && !N && !suffixCommon.length && !prefixCommon.length) return [];
   if (!N) {
     return [
-      ...prefixCommon.map(c => ({ type: "common" as DiffType, value: c })),
+      ...prefixCommon.map(c => ({ type: DiffType.common, value: c })),
       ...A.map(a => ({
-        type: (swapped ? "added" : "removed") as DiffType,
+        type: swapped ? DiffType.added : DiffType.removed,
         value: a
       })),
-      ...suffixCommon.map(c => ({ type: "common" as DiffType, value: c }))
+      ...suffixCommon.map(c => ({ type: DiffType.common, value: c }))
     ];
   }
   const offset = N;
@@ -91,18 +95,18 @@ export default function diff<T>(A: T[], B: T[]): Array<DiffResult<T>> {
       const prev = j;
       if (type === REMOVED) {
         result.unshift({
-          type: (swapped ? "removed" : "added") as DiffType,
+          type: swapped ? DiffType.removed : DiffType.added,
           value: B[b]
         });
         b -= 1;
       } else if (type === ADDED) {
         result.unshift({
-          type: (swapped ? "added" : "removed") as DiffType,
+          type: swapped ? DiffType.added : DiffType.removed,
           value: A[a]
         });
         a -= 1;
       } else {
-        result.unshift({ type: "common" as DiffType, value: A[a] });
+        result.unshift({ type: DiffType.common, value: A[a] });
         a -= 1;
         b -= 1;
       }
@@ -194,8 +198,8 @@ export default function diff<T>(A: T[], B: T[]): Array<DiffResult<T>> {
     );
   }
   return [
-    ...prefixCommon.map(c => ({ type: "common" as DiffType, value: c })),
+    ...prefixCommon.map(c => ({ type: DiffType.common, value: c })),
     ...backTrace(A, B, fp[delta + offset], swapped),
-    ...suffixCommon.map(c => ({ type: "common" as DiffType, value: c }))
+    ...suffixCommon.map(c => ({ type: DiffType.common, value: c }))
   ];
 }
diff --git a/testing/mod.ts b/testing/mod.ts
index 0f6ffefbc..c9cdde0d2 100644
--- a/testing/mod.ts
+++ b/testing/mod.ts
@@ -2,11 +2,16 @@
 
 import { green, red } from "../colors/mod.ts";
 import { assertEqual as prettyAssertEqual } from "./pretty.ts";
-
-interface Constructor {
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  new (...args: any[]): any;
-}
+import {
+  assert as assertImport,
+  equal as AssertEqual,
+  assertStrictEq,
+  assertStrContains,
+  assertMatch,
+  fail,
+  assertThrows,
+  assertThrowsAsync
+} from "./asserts.ts";
 
 export function equal(c: unknown, d: unknown): boolean {
   const seen = new Map();
@@ -36,125 +41,14 @@ export function equal(c: unknown, d: unknown): boolean {
 }
 
 const assertions = {
-  /** Make an assertion, if not `true`, then throw. */
-  assert(expr: boolean, msg = ""): void {
-    if (!expr) {
-      throw new Error(msg);
-    }
-  },
-
-  /** Make an assertion that `actual` and `expected` are equal, deeply. If not
-   * deeply equal, then throw.
-   */
-  equal(actual: unknown, expected: unknown, msg?: string): void {
-    prettyAssertEqual(actual, expected, msg);
-  },
-
-  /** Make an assertion that `actual` and `expected` are strictly equal.  If
-   * not then throw.
-   */
-  strictEqual(actual: unknown, expected: unknown, msg = ""): void {
-    if (actual !== expected) {
-      let actualString: string;
-      let expectedString: string;
-      try {
-        actualString = String(actual);
-      } catch (e) {
-        actualString = "[Cannot display]";
-      }
-      try {
-        expectedString = String(expected);
-      } catch (e) {
-        expectedString = "[Cannot display]";
-      }
-      console.error(
-        "strictEqual failed. actual =",
-        actualString,
-        "expected =",
-        expectedString
-      );
-      if (!msg) {
-        msg = `actual: ${actualString} expected: ${expectedString}`;
-      }
-      throw new Error(msg);
-    }
-  },
-
-  /**
-   * Forcefully throws a failed assertion
-   */
-  fail(msg?: string): void {
-    // eslint-disable-next-line @typescript-eslint/no-use-before-define
-    assert(false, `Failed assertion${msg ? `: ${msg}` : "."}`);
-  },
-
-  /** Executes a function, expecting it to throw.  If it does not, then it
-   * throws.  An error class and a string that should be included in the
-   * error message can also be asserted.
-   */
-  throws(
-    fn: () => void,
-    ErrorClass?: Constructor,
-    msgIncludes = "",
-    msg = ""
-  ): void {
-    let doesThrow = false;
-    try {
-      fn();
-    } catch (e) {
-      if (ErrorClass && !(Object.getPrototypeOf(e) === ErrorClass.prototype)) {
-        msg = `Expected error to be instance of "${ErrorClass.name}"${
-          msg ? `: ${msg}` : "."
-        }`;
-        throw new Error(msg);
-      }
-      if (msgIncludes) {
-        if (!e.message.includes(msgIncludes)) {
-          msg = `Expected error message to include "${msgIncludes}", but got "${
-            e.message
-          }"${msg ? `: ${msg}` : "."}`;
-          throw new Error(msg);
-        }
-      }
-      doesThrow = true;
-    }
-    if (!doesThrow) {
-      msg = `Expected function to throw${msg ? `: ${msg}` : "."}`;
-      throw new Error(msg);
-    }
-  },
-
-  async throwsAsync(
-    fn: () => Promise<void>,
-    ErrorClass?: Constructor,
-    msgIncludes = "",
-    msg = ""
-  ): Promise<void> {
-    let doesThrow = false;
-    try {
-      await fn();
-    } catch (e) {
-      if (ErrorClass && !(Object.getPrototypeOf(e) === ErrorClass.prototype)) {
-        msg = `Expected error to be instance of "${ErrorClass.name}"${
-          msg ? `: ${msg}` : "."
-        }`;
-        throw new Error(msg);
-      }
-      if (msgIncludes) {
-        if (!e.message.includes(msgIncludes)) {
-          msg = `Expected error message to include "${msgIncludes}", but got "${
-            e.message
-          }"${msg ? `: ${msg}` : "."}`;
-          throw new Error(msg);
-        }
-      }
-      doesThrow = true;
-    }
-    if (!doesThrow) {
-      msg = `Expected function to throw${msg ? `: ${msg}` : "."}`;
-      throw new Error(msg);
-    }
-  }
+  assert: assertImport,
+  equal: AssertEqual,
+  strictEqual: assertStrictEq,
+  assertStrContains: assertStrContains,
+  assertMatch: assertMatch,
+  fail: fail,
+  throws: assertThrows,
+  throwsAsync: assertThrowsAsync
 };
 
 type Assert = typeof assertions.assert & typeof assertions;
diff --git a/testing/pretty.ts b/testing/pretty.ts
index 737d9c6dd..05fd86b6f 100644
--- a/testing/pretty.ts
+++ b/testing/pretty.ts
@@ -17,9 +17,9 @@ function createStr(v: unknown): string {
 
 function createColor(diffType: DiffType): (s: string) => string {
   switch (diffType) {
-    case "added":
+    case DiffType.added:
       return (s: string) => green(bold(s));
-    case "removed":
+    case DiffType.removed:
       return (s: string) => red(bold(s));
     default:
       return white;
@@ -28,9 +28,9 @@ function createColor(diffType: DiffType): (s: string) => string {
 
 function createSign(diffType: DiffType): string {
   switch (diffType) {
-    case "added":
+    case DiffType.added:
       return "+   ";
-    case "removed":
+    case DiffType.removed:
       return "-   ";
     default:
       return "    ";
diff --git a/testing/test.ts b/testing/test.ts
index a90ab5dc7..bdebce431 100644
--- a/testing/test.ts
+++ b/testing/test.ts
@@ -1,10 +1,10 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-
 import { test, assert, assertEqual, equal, runIfMain } from "./mod.ts";
 import { assertEqual as prettyAssertEqual } from "./pretty.ts";
 import "./format_test.ts";
 import "./diff_test.ts";
 import "./pretty_test.ts";
+import "./asserts_test.ts";
 
 test(function testingEqual() {
   assert(equal("world", "world"));