diff --git a/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/locales-invalid.js b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/locales-invalid.js
new file mode 100644
index 0000000000..3964ba9018
--- /dev/null
+++ b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/locales-invalid.js
@@ -0,0 +1,20 @@
+// Copyright 2018 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-Intl.RelativeTimeFormat.supportedLocalesOf
+description: Checks error cases for the locales argument to the supportedLocalesOf function.
+info: |
+    Intl.RelativeTimeFormat.supportedLocalesOf ( locales [, options ])
+
+    2. Let requestedLocales be CanonicalizeLocaleList(locales).
+includes: [testIntl.js]
+features: [Intl.RelativeTimeFormat]
+---*/
+
+assert.sameValue(typeof Intl.RelativeTimeFormat.supportedLocalesOf, "function",
+                 "Should support Intl.RelativeTimeFormat.supportedLocalesOf.");
+
+for (const [locales, expectedError] of getInvalidLocaleArguments()) {
+    assert.throws(expectedError, () => Intl.RelativeTimeFormat.supportedLocalesOf(locales));
+}
diff --git a/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-localeMatcher-invalid.js b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-localeMatcher-invalid.js
new file mode 100644
index 0000000000..a1bd71689b
--- /dev/null
+++ b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-localeMatcher-invalid.js
@@ -0,0 +1,34 @@
+// Copyright 2018 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-Intl.RelativeTimeFormat.supportedLocalesOf
+description: Checks handling of invalid values for the localeMatcher option to the supportedLocalesOf function.
+info: |
+    SupportedLocales ( availableLocales, requestedLocales, options )
+
+    1. If options is not undefined, then
+        b. Let matcher be ? GetOption(options, "localeMatcher", "string", «"lookup", "best fit"», "best fit").
+features: [Intl.RelativeTimeFormat]
+---*/
+
+assert.sameValue(typeof Intl.RelativeTimeFormat.supportedLocalesOf, "function",
+                 "Should support Intl.RelativeTimeFormat.supportedLocalesOf.");
+
+const invalidOptions = [
+  null,
+  1,
+  "",
+  "Lookup",
+  "LOOKUP",
+  "lookup\0",
+  "Best fit",
+  "BEST FIT",
+  "best\u00a0fit",
+];
+
+for (const invalidOption of invalidOptions) {
+  assert.throws(RangeError, function() {
+    Intl.RelativeTimeFormat.supportedLocalesOf([], {"localeMatcher": invalidOption});
+  }, `${invalidOption} is an invalid localeMatcher option value`);
+}
diff --git a/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-null.js b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-null.js
new file mode 100644
index 0000000000..807e9f9aff
--- /dev/null
+++ b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-null.js
@@ -0,0 +1,20 @@
+// Copyright 2018 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-Intl.RelativeTimeFormat.supportedLocalesOf
+description: Checks handling of a null options argument to the supportedLocalesOf function.
+info: |
+    SupportedLocales ( availableLocales, requestedLocales, options )
+
+    1. If options is not undefined, then
+        a. Let options be ? ToObject(options).
+features: [Intl.RelativeTimeFormat]
+---*/
+
+assert.sameValue(typeof Intl.RelativeTimeFormat.supportedLocalesOf, "function",
+                 "Should support Intl.RelativeTimeFormat.supportedLocalesOf.");
+
+assert.throws(TypeError, function() {
+  Intl.RelativeTimeFormat.supportedLocalesOf([], null);
+}, "Should throw when passing null as the options argument");
diff --git a/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-toobject.js b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-toobject.js
new file mode 100644
index 0000000000..2f87db4eff
--- /dev/null
+++ b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-toobject.js
@@ -0,0 +1,41 @@
+// Copyright 2018 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-Intl.RelativeTimeFormat.supportedLocalesOf
+description: Checks handling of non-object options arguments to the supportedLocalesOf function.
+info: |
+    SupportedLocales ( availableLocales, requestedLocales, options )
+
+    1. If options is not undefined, then
+        a. Let options be ? ToObject(options).
+features: [Intl.RelativeTimeFormat]
+---*/
+
+assert.sameValue(typeof Intl.RelativeTimeFormat.supportedLocalesOf, "function",
+                 "Should support Intl.RelativeTimeFormat.supportedLocalesOf.");
+
+let called;
+Object.defineProperties(Object.prototype, {
+  "localeMatcher": {
+    get() {
+      ++called;
+      return "best fit";
+    }
+  }
+});
+
+const optionsArguments = [
+  true,
+  "test",
+  7,
+  Symbol(),
+];
+
+for (const options of optionsArguments) {
+  called = 0;
+  const result = Intl.RelativeTimeFormat.supportedLocalesOf([], options);
+  assert.sameValue(Array.isArray(result), true, `Expected array from ${String(options)}`);
+  assert.sameValue(called, 1, `Expected one call from ${String(options)}`);
+}
+
diff --git a/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-undefined.js b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-undefined.js
new file mode 100644
index 0000000000..1a995eae64
--- /dev/null
+++ b/test/intl402/RelativeTimeFormat/constructor/supportedLocalesOf/options-undefined.js
@@ -0,0 +1,26 @@
+// Copyright 2018 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-Intl.RelativeTimeFormat.supportedLocalesOf
+description: Checks handling of an undefined options argument to the supportedLocalesOf function.
+info: |
+    SupportedLocales ( availableLocales, requestedLocales, options )
+
+    1. If options is not undefined, then
+        b. Let matcher be ? GetOption(options, "localeMatcher", "string", «"lookup", "best fit"», "best fit").
+features: [Intl.RelativeTimeFormat]
+---*/
+
+assert.sameValue(typeof Intl.RelativeTimeFormat.supportedLocalesOf, "function",
+                 "Should support Intl.RelativeTimeFormat.supportedLocalesOf.");
+
+Object.defineProperties(Object.prototype, {
+  "localeMatcher": {
+    get() { throw new Error("Should not call localeMatcher getter"); }
+  }
+});
+
+assert.sameValue(Array.isArray(Intl.RelativeTimeFormat.supportedLocalesOf()), true, "No arguments");
+assert.sameValue(Array.isArray(Intl.RelativeTimeFormat.supportedLocalesOf([])), true, "One argument");
+assert.sameValue(Array.isArray(Intl.RelativeTimeFormat.supportedLocalesOf([], undefined)), true, "Two arguments");