Use pretty assertEqual in testing (denoland/deno_std#234)

Original: https://github.com/denoland/deno_std/commit/8fb9f709a67e92634b0be3024dfbc70fb445883c

1 files changed, 8 insertions, 1 deletions

diff --git a/testing/pretty.ts b/testing/pretty.ts
index b27b3ccd7..737d9c6dd 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);
 }