diff --git a/testing/web-platform/tests/webrtc/RTCDataChannel-bufferedAmount.html b/testing/web-platform/tests/webrtc/RTCDataChannel-bufferedAmount.html
index dcd68f85b379..a7f091334f75 100644
--- a/testing/web-platform/tests/webrtc/RTCDataChannel-bufferedAmount.html
+++ b/testing/web-platform/tests/webrtc/RTCDataChannel-bufferedAmount.html
@@ -1175,6 +1175,514 @@
 '
 )
 ;
+promise_test
+(
+async
+t
+=
+>
+{
+const
+[
+channel1
+channel2
+]
+=
+await
+createDataChannelPair
+(
+)
+;
+channel1
+.
+addEventListener
+(
+'
+bufferedamountlow
+'
+t
+.
+step_func_done
+(
+(
+)
+=
+>
+{
+assert_true
+(
+channel1
+.
+bufferedAmount
+<
+=
+channel1
+.
+bufferedAmountLowThreshold
+)
+;
+}
+)
+)
+;
+const
+eventWatcher
+=
+new
+EventWatcher
+(
+t
+channel1
+[
+'
+bufferedamountlow
+'
+]
+)
+;
+channel1
+.
+send
+(
+helloString
+)
+;
+await
+eventWatcher
+.
+wait_for
+(
+[
+'
+bufferedamountlow
+'
+]
+)
+;
+}
+'
+Data
+channel
+bufferedamountlow
+event
+fires
+after
+send
+(
+)
+is
+complete
+'
+)
+;
+promise_test
+(
+async
+t
+=
+>
+{
+const
+[
+channel1
+channel2
+]
+=
+await
+createDataChannelPair
+(
+)
+;
+channel1
+.
+send
+(
+helloString
+)
+;
+assert_equals
+(
+channel1
+.
+bufferedAmount
+helloString
+.
+length
+)
+;
+await
+awaitMessage
+(
+channel2
+)
+;
+assert_equals
+(
+channel1
+.
+bufferedAmount
+0
+)
+;
+}
+'
+Data
+channel
+bufferedamount
+is
+data
+.
+length
+on
+send
+(
+data
+)
+'
+)
+;
+promise_test
+(
+async
+t
+=
+>
+{
+const
+[
+channel1
+channel2
+]
+=
+await
+createDataChannelPair
+(
+)
+;
+channel1
+.
+send
+(
+helloString
+)
+;
+assert_equals
+(
+channel1
+.
+bufferedAmount
+helloString
+.
+length
+)
+;
+assert_equals
+(
+channel1
+.
+bufferedAmount
+helloString
+.
+length
+)
+;
+}
+'
+Data
+channel
+bufferedamount
+returns
+the
+same
+amount
+if
+no
+more
+data
+is
+'
++
+'
+sent
+on
+the
+channel
+'
+)
+;
+promise_test
+(
+async
+t
+=
+>
+{
+const
+[
+channel1
+channel2
+]
+=
+await
+createDataChannelPair
+(
+)
+;
+let
+eventFireCount
+=
+0
+;
+channel1
+.
+addEventListener
+(
+'
+bufferedamountlow
+'
+t
+.
+step_func
+(
+(
+)
+=
+>
+{
+assert_true
+(
+channel1
+.
+bufferedAmount
+<
+=
+channel1
+.
+bufferedAmountLowThreshold
+)
+;
+assert_equals
+(
++
++
+eventFireCount
+1
+)
+;
+}
+)
+)
+;
+const
+eventWatcher
+=
+new
+EventWatcher
+(
+t
+channel1
+[
+'
+bufferedamountlow
+'
+]
+)
+;
+channel1
+.
+send
+(
+helloString
+)
+;
+assert_equals
+(
+channel1
+.
+bufferedAmount
+helloString
+.
+length
+)
+;
+channel1
+.
+send
+(
+helloString
+)
+;
+assert_equals
+(
+channel1
+.
+bufferedAmount
+2
+*
+helloString
+.
+length
+)
+;
+await
+eventWatcher
+.
+wait_for
+(
+[
+'
+bufferedamountlow
+'
+]
+)
+;
+}
+'
+Data
+channel
+bufferedamountlow
+event
+fires
+only
+once
+after
+multiple
+'
++
+'
+consecutive
+send
+(
+)
+calls
+'
+)
+;
+promise_test
+(
+async
+t
+=
+>
+{
+const
+[
+channel1
+channel2
+]
+=
+await
+createDataChannelPair
+(
+)
+;
+const
+eventWatcher
+=
+new
+EventWatcher
+(
+t
+channel1
+[
+'
+bufferedamountlow
+'
+]
+)
+;
+channel1
+.
+send
+(
+helloString
+)
+;
+assert_equals
+(
+channel1
+.
+bufferedAmount
+helloString
+.
+length
+)
+;
+await
+eventWatcher
+.
+wait_for
+(
+[
+'
+bufferedamountlow
+'
+]
+)
+;
+assert_equals
+(
+await
+awaitMessage
+(
+channel2
+)
+helloString
+)
+;
+channel1
+.
+send
+(
+helloString
+)
+;
+assert_equals
+(
+channel1
+.
+bufferedAmount
+helloString
+.
+length
+)
+;
+await
+eventWatcher
+.
+wait_for
+(
+[
+'
+bufferedamountlow
+'
+]
+)
+;
+assert_equals
+(
+await
+awaitMessage
+(
+channel2
+)
+helloString
+)
+;
+}
+'
+Data
+channel
+bufferedamountlow
+event
+fires
+after
+each
+sent
+message
+'
+)
+;
 <
 /
 script