assert: reduce diff noise

Assertion errors that produce a diff show a diff for identical entries in case one side of the comparison has more object properties than the other one. Those lines are now taken into account and will not show up as diverging lines anymore. Refs: #22763 PR-URL: #23048 Refs: #22763 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Shingo Inoue <leko.noor@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>
nodejs · Sep 27, 2018 · 02c44a4 · 02c44a4
1 parent b8a8eed
commit 02c44a4
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Showing 2 changed files with 50 additions and 29 deletions.
diff --git a/lib/internal/assert.js b/lib/internal/assert.js
@@ -205,29 +205,42 @@ function createErrDiff(actual, expected, operator) {
       res += `\n${green}+${white} ${actualLines[i]}`;
       printedLines++;
     // Lines diverge
-    } else if (actualLines[i] !== expectedLines[i]) {
-      if (cur > 1 && i > 2) {
-        if (cur > 4) {
-          res += `\n${blue}...${white}`;
-          skipped = true;
-        } else if (cur > 3) {
-          res += `\n  ${actualLines[i - 2]}`;
+    } else {
+      const expectedLine = expectedLines[i];
+      let actualLine = actualLines[i];
+      let divergingLines = actualLine !== expectedLine &&
+                           (!actualLine.endsWith(',') ||
+                            actualLine.slice(0, -1) !== expectedLine);
+      if (divergingLines &&
+          expectedLine.endsWith(',') &&
+          expectedLine.slice(0, -1) === actualLine) {
+        divergingLines = false;
+        actualLine += ',';
+      }
+      if (divergingLines) {
+        if (cur > 1 && i > 2) {
+          if (cur > 4) {
+            res += `\n${blue}...${white}`;
+            skipped = true;
+          } else if (cur > 3) {
+            res += `\n  ${actualLines[i - 2]}`;
+            printedLines++;
+          }
+          res += `\n  ${actualLines[i - 1]}`;
+          printedLines++;
+        }
+        lastPos = i;
+        res += `\n${green}+${white} ${actualLine}`;
+        other += `\n${red}-${white} ${expectedLine}`;
+        printedLines += 2;
+      // Lines are identical
+      } else {
+        res += other;
+        other = '';
+        if (cur === 1 || i === 0) {
+          res += `\n  ${actualLine}`;
           printedLines++;
         }
-        res += `\n  ${actualLines[i - 1]}`;
-        printedLines++;
-      }
-      lastPos = i;
-      res += `\n${green}+${white} ${actualLines[i]}`;
-      other += `\n${red}-${white} ${expectedLines[i]}`;
-      printedLines += 2;
-    // Lines are identical
-    } else {
-      res += other;
-      other = '';
-      if (cur === 1 || i === 0) {
-        res += `\n  ${actualLines[i]}`;
-        printedLines++;
       }
     }
     // Inspected object to big (Show ~20 rows max)

diff --git a/test/parallel/test-assert-deep.js b/test/parallel/test-assert-deep.js
@@ -65,9 +65,13 @@ assert.deepEqual(arr, buf);
     () => assert.deepStrictEqual(buf2, buf),
     {
       code: 'ERR_ASSERTION',
-      message: `${defaultMsgStartFull}\n\n` +
-               '  Buffer [Uint8Array] [\n    120,\n    121,\n    122,\n' +
-               '+   10,\n+   prop: 1\n-   10\n  ]'
+      message: `${defaultMsgStartFull} ... Lines skipped\n\n` +
+               '  Buffer [Uint8Array] [\n' +
+               '    120,\n' +
+               '...\n' +
+               '    10,\n' +
+               '+   prop: 1\n' +
+               '  ]'
     }
   );
   assert.deepEqual(buf2, buf);
@@ -80,9 +84,13 @@ assert.deepEqual(arr, buf);
     () => assert.deepStrictEqual(arr, arr2),
     {
       code: 'ERR_ASSERTION',
-      message: `${defaultMsgStartFull}\n\n` +
-               '  Uint8Array [\n    120,\n    121,\n    122,\n' +
-               '+   10\n-   10,\n-   prop: 5\n  ]'
+      message: `${defaultMsgStartFull} ... Lines skipped\n\n` +
+               '  Uint8Array [\n' +
+               '    120,\n' +
+               '...\n' +
+               '    10,\n' +
+               '-   prop: 5\n' +
+               '  ]'
     }
   );
   assert.deepEqual(arr, arr2);
@@ -822,7 +830,7 @@ assert.throws(
     code: 'ERR_ASSERTION',
     name: 'AssertionError [ERR_ASSERTION]',
     message: `${defaultMsgStartFull}\n\n  ` +
-             '{\n+   a: 4\n-   a: 4,\n-   b: true\n  }'
+             '{\n    a: 4,\n-   b: true\n  }'
   });
 assert.throws(
   () => assert.deepStrictEqual(['a'], { 0: 'a' }),
@@ -891,7 +899,7 @@ assert.deepStrictEqual(obj1, obj2);
   assert.throws(
     () => assert.deepStrictEqual(arrProxy, [1, 2, 3]),
     { message: `${defaultMsgStartFull}\n\n` +
-               '  [\n    1,\n+   2\n-   2,\n-   3\n  ]' }
+               '  [\n    1,\n    2,\n-   3\n  ]' }
   );
   util.inspect.defaultOptions = tmp;