test: add comment for dual assertions and wrap assert.ok in try/catch

Author: mertcanaltin

test/es-module/test-typescript-commonjs.mjs

@@ -68,15 +68,28 @@ test('expect failure of an .mts file with CommonJS syntax', async () => {
 
   const expectedWarning = `Failed to load the ES module: ${testFilePath}. Make sure to set "type": "module" in the nearest package.json file or use the .mjs extension.`;
 
+  // First assertion: check that stderr contains a generic pattern for the ES module load failure.
+  // This ensures that at a minimum the error message structure is as expected.
   assert.match(
     result.stderr,
     /Failed to load the ES module:.*test-cts-but-module-syntax\.cts/
   );
 
-  assert.ok(
-    result.stderr.includes(expectedWarning),
-    `Expected stderr to include: ${expectedWarning}`
-  );
+  // Second assertion: verify that stderr includes the complete expected warning message.
+  // We use a try/catch here to improve the error output, providing more context if the assertion fails.
+  // Having two assertions ensures that:
+  //   1. We first confirm the error message follows the expected general format.
+  //   2. We then check that the specific warning (with file path and message details) is present.
+  try {
+    assert.ok(
+      result.stderr.includes(expectedWarning),
+      `Expected stderr to include: ${expectedWarning}`
+    );
+  } catch (error) {
+    console.error('Detailed error: The stderr did not include the expected warning:', error);
+    throw error;
+  }
+
 
   assert.strictEqual(result.code, 1);
 });