diff --git a/lib/internal/assert/assertion_error.js b/lib/internal/assert/assertion_error.js
index 048d7be75fc662..2cbd36c67f8876 100644
--- a/lib/internal/assert/assertion_error.js
+++ b/lib/internal/assert/assertion_error.js
@@ -14,6 +14,8 @@ let white = '';
 
 const kReadableOperator = {
   deepStrictEqual: 'Expected values to be strictly deep-equal:',
+  equal: 'Expected values to be loosely equal:',
+  notEqualUnequal: 'Expected values not to be loosely equal:',
   strictEqual: 'Expected values to be strictly equal:',
   strictEqualObject: 'Expected "actual" to be reference-equal to "expected":',
   deepEqual: 'Expected values to be loosely deep-equal:',
diff --git a/test/parallel/test-assert-assertion-error.js b/test/parallel/test-assert-assertion-error.js
new file mode 100644
index 00000000000000..ba39cf18fb5f11
--- /dev/null
+++ b/test/parallel/test-assert-assertion-error.js
@@ -0,0 +1,27 @@
+'use strict';
+require('../common');
+
+// Test some edge cases for AssertionError that are not tested elsewhere.
+const assert = require('assert');
+
+{
+  const err = new assert.AssertionError({ operator: 'equal',
+                                          actual: 'come on',
+                                          expected: 'fhqwhgads',
+  });
+
+  assert.strictEqual(err.message,
+                     "Expected values to be loosely equal:\n\n'come on'\n\n" +
+                     "should loosely equal\n\n'fhqwhgads'");
+}
+
+{
+  const err = new assert.AssertionError({ operator: 'notEqual',
+                                          actual: 'come on',
+                                          expected: 'fhqwhgads',
+  });
+
+  assert.strictEqual(err.message,
+                     'Expected values not to be loosely equal:\n\n' +
+                     "'come on'\n\nshould not loosely equal\n\n'fhqwhgads'");
+}