diff --git a/test/built-ins/String/prototype/trimEnd/this-value-boolean.js b/test/built-ins/String/prototype/trimEnd/this-value-boolean.js
new file mode 100644
index 0000000000000000000000000000000000000000..1a695e3b97476e8398e14c706335bc10d62a7cd7
--- /dev/null
+++ b/test/built-ins/String/prototype/trimEnd/this-value-boolean.js
@@ -0,0 +1,21 @@
+// Copyright (c) 2017 Valerie Young.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: pending
+description: Behavoir when "this" value is a boolean.
+---*/
+
+var trimStart = String.prototype.trimStart
+
+assert.sameValue(
+    trimStart.call(true),
+    'true',
+    'String.prototype.trimStart.call(true)'
+);
+
+assert.sameValue(
+    String.prototype.trimStart.call(false),
+    'false',
+    'String.prototype.trimStart.call(false)'
+);
diff --git a/test/built-ins/String/prototype/trimEnd/this-value-symbol-typeerror.js b/test/built-ins/String/prototype/trimEnd/this-value-symbol-typeerror.js
new file mode 100644
index 0000000000000000000000000000000000000000..e9f32fb76b9b775948fea96136d2e39108649777
--- /dev/null
+++ b/test/built-ins/String/prototype/trimEnd/this-value-symbol-typeerror.js
@@ -0,0 +1,21 @@
+// Copyright (C) 2017 Valerie Young. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: pending
+description: Type error when "this" value is a Symbol
+info: |
+  TrimString
+  2. Let S be ? ToString(str).
+
+  ToString
+  Argument Type: Symbol
+  Result: Throw a TypeError exception
+---*/
+
+var trimEnd = String.prototype.trimEnd;
+var symbol = Symbol()
+
+assert.throws(TypeError, function() {
+  trimEnd.call(symbol);
+}, 'Symbol()');
diff --git a/test/built-ins/String/prototype/trimStart/this-value-boolean.js b/test/built-ins/String/prototype/trimStart/this-value-boolean.js
new file mode 100644
index 0000000000000000000000000000000000000000..1a695e3b97476e8398e14c706335bc10d62a7cd7
--- /dev/null
+++ b/test/built-ins/String/prototype/trimStart/this-value-boolean.js
@@ -0,0 +1,21 @@
+// Copyright (c) 2017 Valerie Young.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: pending
+description: Behavoir when "this" value is a boolean.
+---*/
+
+var trimStart = String.prototype.trimStart
+
+assert.sameValue(
+    trimStart.call(true),
+    'true',
+    'String.prototype.trimStart.call(true)'
+);
+
+assert.sameValue(
+    String.prototype.trimStart.call(false),
+    'false',
+    'String.prototype.trimStart.call(false)'
+);
diff --git a/test/built-ins/String/prototype/trimStart/this-value-symbol-typeerror.js b/test/built-ins/String/prototype/trimStart/this-value-symbol-typeerror.js
new file mode 100644
index 0000000000000000000000000000000000000000..b3b87c63f8cd188a4ea3356f8c4123a4109c3606
--- /dev/null
+++ b/test/built-ins/String/prototype/trimStart/this-value-symbol-typeerror.js
@@ -0,0 +1,21 @@
+// Copyright (C) 2017 Valerie Young. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: pending
+description: Type error when "this" value is a Symbol
+info: |
+  TrimString
+  2. Let S be ? ToString(str).
+
+  ToString
+  Argument Type: Symbol
+  Result: Throw a TypeError exception
+---*/
+
+var trimStart = String.prototype.trimStart;
+var symbol = Symbol()
+
+assert.throws(TypeError, function() {
+  trimStart.call(symbol);
+}, 'Symbol()');