diff --git a/test/built-ins/Array/prototype/concat/Array.prototype.concat_large-typed-array.js b/test/built-ins/Array/prototype/concat/Array.prototype.concat_large-typed-array.js
index 361a990748..a7e0beca81 100644
--- a/test/built-ins/Array/prototype/concat/Array.prototype.concat_large-typed-array.js
+++ b/test/built-ins/Array/prototype/concat/Array.prototype.concat_large-typed-array.js
@@ -16,22 +16,13 @@ function concatTypedArray(type, elems, modulo) {
     ta_by_len[i] = items[i] = modulo === false ? i : elems % modulo;
   }
   var ta = new type(items);
-  assert(
-    compareArray([].concat(ta, ta), [ta, ta]),
-    'compareArray([].concat(ta, ta), [ta, ta]) must return true'
-  );
+  assert.compareArray([].concat(ta, ta), [ta, ta]);
   ta[Symbol.isConcatSpreadable] = true;
-  assert.compareArray([].concat(ta), items, '[].concat(new type(items)) returns items');
+  assert.compareArray([].concat(ta), items);
 
-  assert(
-    compareArray([].concat(ta_by_len, ta_by_len), [ta_by_len, ta_by_len]),
-    'compareArray([].concat(ta_by_len, ta_by_len), [ta_by_len, ta_by_len]) must return true'
-  );
+  assert.compareArray([].concat(ta_by_len, ta_by_len), [ta_by_len, ta_by_len]);
   ta_by_len[Symbol.isConcatSpreadable] = true;
-  assert(
-    compareArray([].concat(ta_by_len), items),
-    'compareArray([].concat(ta_by_len), items) must return true'
-  );
+  assert.compareArray([].concat(ta_by_len), items);
 
   // TypedArray with fake `length`.
   ta = new type(1);
@@ -43,7 +34,7 @@ function concatTypedArray(type, elems, modulo) {
     value: 4000
   });
   ta[Symbol.isConcatSpreadable] = true;
-  assert.compareArray([].concat(ta), expected, '[].concat(new type(1)) returns expected');
+  assert.compareArray([].concat(ta), expected);
 }
 
 var max = [Math.pow(2, 8), Math.pow(2, 16), Math.pow(2, 32), false, false];
diff --git a/test/built-ins/Array/prototype/concat/Array.prototype.concat_small-typed-array.js b/test/built-ins/Array/prototype/concat/Array.prototype.concat_small-typed-array.js
index 4c8763a9d9..bca9ae1641 100644
--- a/test/built-ins/Array/prototype/concat/Array.prototype.concat_small-typed-array.js
+++ b/test/built-ins/Array/prototype/concat/Array.prototype.concat_small-typed-array.js
@@ -16,22 +16,13 @@ function concatTypedArray(type, elems, modulo) {
     ta_by_len[i] = items[i] = modulo === false ? i : elems % modulo;
   }
   var ta = new type(items);
-  assert(
-    compareArray([].concat(ta, ta), [ta, ta]),
-    'compareArray([].concat(ta, ta), [ta, ta]) must return true'
-  );
+  assert.compareArray([].concat(ta, ta), [ta, ta]);
   ta[Symbol.isConcatSpreadable] = true;
-  assert.compareArray([].concat(ta), items, '[].concat(new type(items)) returns items');
+  assert.compareArray([].concat(ta), items);
 
-  assert(
-    compareArray([].concat(ta_by_len, ta_by_len), [ta_by_len, ta_by_len]),
-    'compareArray([].concat(ta_by_len, ta_by_len), [ta_by_len, ta_by_len]) must return true'
-  );
+  assert.compareArray([].concat(ta_by_len, ta_by_len), [ta_by_len, ta_by_len]);
   ta_by_len[Symbol.isConcatSpreadable] = true;
-  assert(
-    compareArray([].concat(ta_by_len), items),
-    'compareArray([].concat(ta_by_len), items) must return true'
-  );
+  assert.compareArray([].concat(ta_by_len), items);
 
   // TypedArray with fake `length`.
   ta = new type(1);
@@ -43,7 +34,7 @@ function concatTypedArray(type, elems, modulo) {
     value: 4000
   });
   ta[Symbol.isConcatSpreadable] = true;
-  assert.compareArray([].concat(ta), expected, '[].concat(new type(1)) returns expected');
+  assert.compareArray([].concat(ta), expected);
 }
 var max = [Math.pow(2, 8), Math.pow(2, 16), Math.pow(2, 32), false, false];
 [
diff --git a/test/built-ins/Array/prototype/copyWithin/non-negative-target-and-start.js b/test/built-ins/Array/prototype/copyWithin/non-negative-target-and-start.js
index cf8f60912f..41b3f8e4b1 100644
--- a/test/built-ins/Array/prototype/copyWithin/non-negative-target-and-start.js
+++ b/test/built-ins/Array/prototype/copyWithin/non-negative-target-and-start.js
@@ -31,18 +31,22 @@ info: |
 includes: [compareArray.js]
 ---*/
 
-assert(compareArray(
-  ['a', 'b', 'c', 'd', 'e', 'f'].copyWithin(0, 0), ['a', 'b', 'c', 'd', 'e', 'f']
-), 'compareArray( ["a", "b", "c", "d", "e", "f"].copyWithin(0, 0), ["a", "b", "c", "d", "e", "f"] ) must return true');
+assert.compareArray(
+  ['a', 'b', 'c', 'd', 'e', 'f'].copyWithin(0, 0),
+  ['a', 'b', 'c', 'd', 'e', 'f']
+);
 
-assert(compareArray(
-  ['a', 'b', 'c', 'd', 'e', 'f'].copyWithin(0, 2), ['c', 'd', 'e', 'f', 'e', 'f']
-), 'compareArray( ["a", "b", "c", "d", "e", "f"].copyWithin(0, 2), ["c", "d", "e", "f", "e", "f"] ) must return true');
+assert.compareArray(
+  ['a', 'b', 'c', 'd', 'e', 'f'].copyWithin(0, 2),
+  ['c', 'd', 'e', 'f', 'e', 'f']
+);
 
-assert(compareArray(
-  ['a', 'b', 'c', 'd', 'e', 'f'].copyWithin(3, 0), ['a', 'b', 'c', 'a', 'b', 'c']
-), 'compareArray( ["a", "b", "c", "d", "e", "f"].copyWithin(3, 0), ["a", "b", "c", "a", "b", "c"] ) must return true');
+assert.compareArray(
+  ['a', 'b', 'c', 'd', 'e', 'f'].copyWithin(3, 0),
+  ['a', 'b', 'c', 'a', 'b', 'c']
+);
 
-assert(compareArray(
-  [0, 1, 2, 3, 4, 5].copyWithin(1, 4), [0, 4, 5, 3, 4, 5]
-), 'compareArray( [0, 1, 2, 3, 4, 5].copyWithin(1, 4), [0, 4, 5, 3, 4, 5] ) must return true');
+assert.compareArray(
+  [0, 1, 2, 3, 4, 5].copyWithin(1, 4),
+  [0, 4, 5, 3, 4, 5]
+);