BetterThanTomorrow#1007: show diff between expected and actual in tes…

…t runner

src/extension-test/unit/test-runner-test.ts

@@ -167,4 +167,35 @@ orange`
 apple`
     );
   });
+
+  it('can produce detailed messages with diffs', () => {
+    expect(
+      cider.detailedMessage({
+        type: 'fail',
+        ns: 'core',
+        context: 'ctx',
+        index: 2,
+        expected: '{:key1 "value1", :key2 "value2"}',
+        actual: '{:key1 "wrongValue", :key2 "value2"}',
+        var: 'test',
+        file: 'core.clj',
+        line: 10,
+        message: 'Values do not match',
+        diffs: [
+          [
+            '{:key1 "wrongValue", :key2 "value2"}',
+            ['{:key1 "value1", :key2 "value2"}', '{:key1 "wrongValue"}'],
+          ],
+        ],
+      })
+    ).toBe(`; FAIL in core/test (core.clj:10):
+; ctx: Values do not match
+; expected:
+{:key1 "value1", :key2 "value2"}
+; actual:
+{:key1 "wrongValue", :key2 "value2"}
+; diff:
+- {:key1 "value1", :key2 "value2"}
++ {:key1 "wrongValue"}`);
+  });
 });

src/nrepl/cider.ts

@@ -1,3 +1,4 @@
+import { diff } from 'semver';
 // https://github.com/clojure-emacs/cider-nrepl/blob/a740583c3aa8b582f3097611787a276775131d32/src/cider/nrepl/middleware/test.clj#L45
 export interface TestSummary {
   ns: number;
@@ -142,6 +143,31 @@ export function lineInformation(result: TestResult): string {
   return ` (${result.file}:${result.line})`;
 }
 
+function getDiffMessages(result: TestResult): string[] {
+  const diffs = result.diffs;
+  const messages: string[] = [];
+
+  if (diffs && Array.isArray(diffs)) {
+    diffs.forEach((diffPair: [string, [string, string]]) => {
+      if (Array.isArray(diffPair) && diffPair.length === 2) {
+        const [_, [removed, added]] = diffPair;
+
+        if (removed || added) {
+          messages.push('; diff:');
+          messages.push(removed ? `- ${removed.trim()}` : '');
+          if (added) {
+            messages.push(`+ ${added.trim()}`);
+          }
+        }
+      } else {
+        console.warn('Invalid diff pair format:', diffPair);
+      }
+    });
+  }
+
+  return messages;
+}
+
 // Return a detailed message about why a test failed.
 // If the test passed, return the empty string.
 // The message contains "comment" lines that are prepended with ;
@@ -167,12 +193,18 @@ export function detailedMessage(result: TestResult): string | undefined {
     if (message) {
       messages.push(`; ${message}`);
     }
+
     if (result.expected) {
       messages.push(`; expected:\n${result.expected}`);
     }
     if (result.actual) {
       messages.push(`; actual:\n${result.actual}`);
     }
+
+    const diffMessages = getDiffMessages(result);
+    if (diffMessages.length > 0) {
+      messages.push(...diffMessages);
+    }
   }
   return messages.length > 0 ? messages.join('\n') : undefined;
 }

src/testRunner.ts

@@ -139,6 +139,7 @@ async function onTestResult(
         run.errored(assertion, new vscode.TestMessage(cider.shortMessage(result)));
         break;
       case 'fail':
+        run.failed(assertion, new vscode.TestMessage(cider.detailedMessage(result)));
       default:
         run.failed(assertion, new vscode.TestMessage(cider.shortMessage(result)));
         break;