diff --git a/testing/web-platform/tests/custom-elements/CustomElementRegistry-getName.tentative.html b/testing/web-platform/tests/custom-elements/CustomElementRegistry-getName.tentative.html
new file mode 100644
index 000000000000..5753d2d1ed1d
--- /dev/null
+++ b/testing/web-platform/tests/custom-elements/CustomElementRegistry-getName.tentative.html
@@ -0,0 +1,662 @@
+<
+!
+DOCTYPE
+html
+>
+<
+title
+>
+Custom
+Elements
+:
+CustomElementRegistry
+.
+getName
+function
+<
+/
+title
+>
+<
+meta
+name
+=
+"
+author
+"
+title
+=
+"
+Keith
+Cirkel
+"
+href
+=
+"
+mailto
+:
+keithamus
+github
+.
+com
+"
+>
+<
+meta
+name
+=
+"
+assert
+"
+content
+=
+"
+CustomElementRegistry
+.
+getName
+function
+exists
+"
+>
+<
+script
+src
+=
+"
+/
+resources
+/
+testharness
+.
+js
+"
+>
+<
+/
+script
+>
+<
+script
+src
+=
+"
+/
+resources
+/
+testharnessreport
+.
+js
+"
+>
+<
+/
+script
+>
+<
+script
+>
+test
+(
+function
+(
+)
+{
+assert_equals
+(
+customElements
+.
+getName
+(
+class
+extends
+HTMLElement
+{
+}
+)
+null
+)
+;
+}
+'
+customElements
+.
+getName
+must
+return
+null
+when
+the
+registry
+does
+not
+contain
+an
+entry
+with
+the
+given
+constructor
+'
+)
+;
+test
+(
+function
+(
+)
+{
+assert_throws_js
+(
+TypeError
+function
+(
+)
+{
+customElements
+.
+getName
+(
+undefined
+)
+;
+}
+'
+customElements
+.
+getName
+must
+throw
+a
+TypeError
+when
+the
+element
+interface
+is
+undefined
+'
+)
+;
+assert_throws_js
+(
+TypeError
+function
+(
+)
+{
+customElements
+.
+getName
+(
+null
+)
+;
+}
+'
+customElements
+.
+getName
+must
+throw
+a
+TypeError
+when
+the
+element
+interface
+is
+null
+'
+)
+;
+assert_throws_js
+(
+TypeError
+function
+(
+)
+{
+customElements
+.
+getName
+(
+'
+foo
+-
+bar
+'
+)
+;
+}
+'
+customElements
+.
+getName
+must
+throw
+a
+TypeError
+when
+the
+element
+interface
+is
+a
+string
+'
+)
+;
+assert_throws_js
+(
+TypeError
+function
+(
+)
+{
+customElements
+.
+getName
+(
+1
+)
+;
+}
+'
+customElements
+.
+getName
+must
+throw
+a
+TypeError
+when
+the
+element
+interface
+is
+a
+number
+'
+)
+;
+assert_throws_js
+(
+TypeError
+function
+(
+)
+{
+customElements
+.
+getName
+(
+{
+}
+)
+;
+}
+'
+customElements
+.
+getName
+must
+throw
+a
+TypeError
+when
+the
+element
+interface
+is
+an
+object
+'
+)
+;
+assert_throws_js
+(
+TypeError
+function
+(
+)
+{
+customElements
+.
+getName
+(
+[
+]
+)
+}
+'
+customElements
+.
+getName
+must
+throw
+a
+TypeError
+when
+the
+element
+interface
+is
+an
+array
+'
+)
+;
+}
+'
+customElements
+.
+getName
+must
+throw
+when
+the
+element
+interface
+is
+not
+a
+constructor
+'
+)
+;
+test
+(
+function
+(
+)
+{
+class
+OtherExistingCustomElement
+extends
+HTMLElement
+{
+}
+;
+class
+SecondExistingCustomElement
+extends
+HTMLElement
+{
+}
+;
+assert_throws_js
+(
+TypeError
+function
+(
+)
+{
+customElements
+.
+getName
+(
+customElements
+.
+getName
+(
+OtherExistingCustomElement
+)
+)
+;
+}
+'
+customElements
+.
+getName
+must
+throw
+a
+TypeError
+when
+the
+element
+interface
+is
+undefined
+'
+)
+;
+customElements
+.
+define
+(
+'
+other
+-
+existing
+-
+custom
+-
+element
+'
+OtherExistingCustomElement
+)
+;
+customElements
+.
+define
+(
+'
+second
+-
+existing
+-
+custom
+-
+element
+'
+SecondExistingCustomElement
+)
+;
+assert_equals
+(
+customElements
+.
+getName
+(
+OtherExistingCustomElement
+)
+'
+other
+-
+existing
+-
+custom
+-
+element
+'
+)
+;
+assert_equals
+(
+customElements
+.
+getName
+(
+SecondExistingCustomElement
+)
+'
+second
+-
+existing
+-
+custom
+-
+element
+'
+)
+;
+}
+'
+customElements
+.
+getName
+returns
+the
+name
+of
+the
+entry
+with
+the
+given
+constructor
+when
+there
+is
+a
+matching
+entry
+.
+'
+)
+;
+test
+(
+function
+(
+)
+{
+class
+ButtonCustomBuiltInElement
+extends
+HTMLButtonElement
+{
+}
+;
+class
+InputCustomBuiltInElement
+extends
+HTMLInputElement
+{
+}
+;
+customElements
+.
+define
+(
+'
+button
+-
+custom
+-
+built
+-
+in
+-
+element
+'
+ButtonCustomBuiltInElement
+{
+extends
+:
+'
+button
+'
+}
+)
+;
+customElements
+.
+define
+(
+'
+input
+-
+custom
+-
+built
+-
+in
+-
+element
+'
+InputCustomBuiltInElement
+{
+extends
+:
+'
+input
+'
+}
+)
+;
+assert_equals
+(
+customElements
+.
+getName
+(
+ButtonCustomBuiltInElement
+)
+'
+button
+-
+custom
+-
+built
+-
+in
+-
+element
+'
+)
+;
+assert_equals
+(
+customElements
+.
+getName
+(
+InputCustomBuiltInElement
+)
+'
+input
+-
+custom
+-
+built
+-
+in
+-
+element
+'
+)
+;
+}
+'
+customElements
+.
+getName
+returns
+the
+name
+of
+the
+entry
+with
+the
+given
+customized
+built
+in
+constructor
+when
+there
+is
+a
+matching
+entry
+.
+'
+)
+;
+<
+/
+script
+>
diff --git a/testing/web-platform/tests/custom-elements/CustomElementRegistry.html b/testing/web-platform/tests/custom-elements/CustomElementRegistry.html
index 78e0a6e37404..5ee9fbec94bc 100644
--- a/testing/web-platform/tests/custom-elements/CustomElementRegistry.html
+++ b/testing/web-platform/tests/custom-elements/CustomElementRegistry.html
@@ -5666,567 +5666,6 @@
 (
 )
 {
-assert_equals
-(
-customElements
-.
-getName
-(
-class
-extends
-HTMLElement
-{
-}
-)
-null
-)
-;
-}
-'
-customElements
-.
-getName
-must
-return
-null
-when
-the
-registry
-does
-not
-contain
-an
-entry
-with
-the
-given
-constructor
-'
-)
-;
-test
-(
-function
-(
-)
-{
-assert_throws_js
-(
-TypeError
-function
-(
-)
-{
-customElements
-.
-getName
-(
-undefined
-)
-;
-}
-'
-customElements
-.
-getName
-must
-throw
-a
-TypeError
-when
-the
-element
-interface
-is
-undefined
-'
-)
-;
-assert_throws_js
-(
-TypeError
-function
-(
-)
-{
-customElements
-.
-getName
-(
-null
-)
-;
-}
-'
-customElements
-.
-getName
-must
-throw
-a
-TypeError
-when
-the
-element
-interface
-is
-null
-'
-)
-;
-assert_throws_js
-(
-TypeError
-function
-(
-)
-{
-customElements
-.
-getName
-(
-'
-foo
--
-bar
-'
-)
-;
-}
-'
-customElements
-.
-getName
-must
-throw
-a
-TypeError
-when
-the
-element
-interface
-is
-a
-string
-'
-)
-;
-assert_throws_js
-(
-TypeError
-function
-(
-)
-{
-customElements
-.
-getName
-(
-1
-)
-;
-}
-'
-customElements
-.
-getName
-must
-throw
-a
-TypeError
-when
-the
-element
-interface
-is
-a
-number
-'
-)
-;
-assert_throws_js
-(
-TypeError
-function
-(
-)
-{
-customElements
-.
-getName
-(
-{
-}
-)
-;
-}
-'
-customElements
-.
-getName
-must
-throw
-a
-TypeError
-when
-the
-element
-interface
-is
-an
-object
-'
-)
-;
-assert_throws_js
-(
-TypeError
-function
-(
-)
-{
-customElements
-.
-getName
-(
-[
-]
-)
-}
-'
-customElements
-.
-getName
-must
-throw
-a
-TypeError
-when
-the
-element
-interface
-is
-an
-array
-'
-)
-;
-}
-'
-customElements
-.
-getName
-must
-throw
-when
-the
-element
-interface
-is
-not
-a
-constructor
-'
-)
-;
-test
-(
-function
-(
-)
-{
-class
-OtherExistingCustomElement
-extends
-HTMLElement
-{
-}
-;
-class
-SecondExistingCustomElement
-extends
-HTMLElement
-{
-}
-;
-assert_throws_js
-(
-TypeError
-function
-(
-)
-{
-customElements
-.
-getName
-(
-customElements
-.
-getName
-(
-OtherExistingCustomElement
-)
-)
-;
-}
-'
-customElements
-.
-getName
-must
-throw
-a
-TypeError
-when
-the
-element
-interface
-is
-undefined
-'
-)
-;
-customElements
-.
-define
-(
-'
-other
--
-existing
--
-custom
--
-element
-'
-OtherExistingCustomElement
-)
-;
-customElements
-.
-define
-(
-'
-second
--
-existing
--
-custom
--
-element
-'
-SecondExistingCustomElement
-)
-;
-assert_equals
-(
-customElements
-.
-getName
-(
-OtherExistingCustomElement
-)
-'
-other
--
-existing
--
-custom
--
-element
-'
-)
-;
-assert_equals
-(
-customElements
-.
-getName
-(
-SecondExistingCustomElement
-)
-'
-second
--
-existing
--
-custom
--
-element
-'
-)
-;
-}
-'
-customElements
-.
-getName
-returns
-the
-name
-of
-the
-entry
-with
-the
-given
-constructor
-when
-there
-is
-a
-matching
-entry
-.
-'
-)
-;
-test
-(
-function
-(
-)
-{
-class
-ButtonCustomBuiltInElement
-extends
-HTMLButtonElement
-{
-}
-;
-class
-InputCustomBuiltInElement
-extends
-HTMLInputElement
-{
-}
-;
-customElements
-.
-define
-(
-'
-button
--
-custom
--
-built
--
-in
--
-element
-'
-ButtonCustomBuiltInElement
-{
-extends
-:
-'
-button
-'
-}
-)
-;
-customElements
-.
-define
-(
-'
-input
--
-custom
--
-built
--
-in
--
-element
-'
-InputCustomBuiltInElement
-{
-extends
-:
-'
-input
-'
-}
-)
-;
-assert_equals
-(
-customElements
-.
-getName
-(
-ButtonCustomBuiltInElement
-)
-'
-button
--
-custom
--
-built
--
-in
--
-element
-'
-)
-;
-assert_equals
-(
-customElements
-.
-getName
-(
-InputCustomBuiltInElement
-)
-'
-input
--
-custom
--
-built
--
-in
--
-element
-'
-)
-;
-}
-'
-customElements
-.
-getName
-returns
-the
-name
-of
-the
-entry
-with
-the
-given
-customized
-built
-in
-constructor
-when
-there
-is
-a
-matching
-entry
-.
-'
-)
-;
-test
-(
-function
-(
-)
-{
 assert_true
 (
 customElements