[inset-area] Add interpolation wpt test

Bug: 1477314
Change-Id: I8afd8ed73018685cef7a42f6bae815f036fd9c5e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5059274
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1229891}
diff --git a/css/css-anchor-position/inset-area-interpolation.html b/css/css-anchor-position/inset-area-interpolation.html
new file mode 100644
index 0000000..29fe76c
--- /dev/null
+++ b/css/css-anchor-position/inset-area-interpolation.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<title>CSS Anchor Positioning: inset-area interpolation</title>
+<link rel="help" href="https://drafts.csswg.org/css-anchor-position/#inset-area">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/interpolation-testcommon.js"></script>
+<body>
+<script>
+  test_no_interpolation({
+    property: "inset-area",
+    from: "none",
+    to: "all / left"
+  });
+</script>