From 39fde3a454b6bcc7daa6bca4fb7f4317550e9e58 Mon Sep 17 00:00:00 2001
From: Vincent LE GOFF <g_n_s@hotmail.fr>
Date: Tue, 5 Mar 2019 02:03:50 +0100
Subject: [PATCH] Use pretty assertEqual in testing (denoland/deno_std#234)

Original: https://github.com/denoland/deno_std/commit/8fb9f709a67e92634b0be3024dfbc70fb445883c
---
 testing/mod.ts    | 30 ++++--------------------------
 testing/pretty.ts |  9 ++++++++-
 testing/test.ts   |  7 ++-----
 3 files changed, 14 insertions(+), 32 deletions(-)

diff --git a/testing/mod.ts b/testing/mod.ts
index c1bf2015b1..0f6ffefbc4 100644
--- a/testing/mod.ts
+++ b/testing/mod.ts
@@ -1,6 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 
 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
@@ -46,30 +47,7 @@ const assertions = {
    * deeply equal, then throw.
    */
   equal(actual: unknown, expected: unknown, msg?: string): void {
-    if (!equal(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(
-        "assertEqual failed. actual =",
-        actualString,
-        "expected =",
-        expectedString
-      );
-      if (!msg) {
-        msg = `actual: ${actualString} expected: ${expectedString}`;
-      }
-      throw new Error(msg);
-    }
+    prettyAssertEqual(actual, expected, msg);
   },
 
   /** Make an assertion that `actual` and `expected` are strictly equal.  If
@@ -187,10 +165,10 @@ Object.assign(assertions.assert, assertions);
 export const assert = assertions.assert as Assert;
 
 /**
- * An alias to assert.equal
+ * Alias to pretty.assertEqual
  * @deprecated
  */
-export const assertEqual = assert.equal;
+export const assertEqual = prettyAssertEqual;
 
 export type TestFunction = () => void | Promise<void>;
 
diff --git a/testing/pretty.ts b/testing/pretty.ts
index b27b3ccd75..737d9c6ddc 100644
--- a/testing/pretty.ts
+++ b/testing/pretty.ts
@@ -55,7 +55,11 @@ function buildMessage(diffResult: ReadonlyArray<DiffResult<string>>): string[] {
   return messages;
 }
 
-export function assertEqual(actual: unknown, expected: unknown): void {
+export function assertEqual(
+  actual: unknown,
+  expected: unknown,
+  msg?: string
+): void {
   if (equal(actual, expected)) {
     return;
   }
@@ -71,5 +75,8 @@ export function assertEqual(actual: unknown, expected: unknown): void {
   } catch (e) {
     message = `\n${red(CAN_NOT_DISPLAY)} + \n\n`;
   }
+  if (msg) {
+    message = msg;
+  }
   throw new Error(message);
 }
diff --git a/testing/test.ts b/testing/test.ts
index 7182a5783e..a90ab5dc7c 100644
--- a/testing/test.ts
+++ b/testing/test.ts
@@ -1,6 +1,7 @@
 // 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";
@@ -31,7 +32,7 @@ test(function testingAssertEqual() {
   const a = Object.create(null);
   a.b = "foo";
   assert.equal(a, a);
-  assert(assertEqual === assert.equal);
+  assert(assertEqual === prettyAssertEqual);
 });
 
 test(function testingAssertFail() {
@@ -52,8 +53,6 @@ test(function testingAssertEqualActualUncoercable() {
     assert.equal(a, "bar");
   } catch (e) {
     didThrow = true;
-    console.log(e.message);
-    assert(e.message === "actual: [Cannot display] expected: bar");
   }
   assert(didThrow);
 });
@@ -65,8 +64,6 @@ test(function testingAssertEqualExpectedUncoercable() {
     assert.equal("bar", a);
   } catch (e) {
     didThrow = true;
-    console.log(e.message);
-    assert(e.message === "actual: bar expected: [Cannot display]");
   }
   assert(didThrow);
 });