From b03e829a498be9a8f6059194522867cdcff488a7 Mon Sep 17 00:00:00 2001
From: Sam Atkins <sam@ladybird.org>
Date: Wed, 6 Aug 2025 11:02:11 +0100
Subject: [PATCH] Tests: Import WPT tests for CSS env()

---
 .../css/css-env/at-supports.tentative.txt     |  6 ++
 .../env-in-custom-properties.tentative.txt    |  7 +++
 .../wpt-import/css/css-env/env-parsing.txt    | 14 +++++
 .../css-env/fallback-nested-var.tentative.txt |  6 ++
 .../css/css-env/indexed-env.tentative.txt     | 14 +++++
 .../seralization-round-tripping.tentative.txt |  6 ++
 .../css/css-env/supports-script.tentative.txt |  6 ++
 .../css/css-env/syntax.tentative.txt          | 24 ++++++++
 ...-env-names-override-previous.tentative.txt |  6 ++
 .../css/css-env/at-supports.tentative.html    | 22 +++++++
 .../env-in-custom-properties.tentative.html   | 35 ++++++++++++
 .../wpt-import/css/css-env/env-parsing.html   | 21 +++++++
 .../fallback-nested-var.tentative.html        | 23 ++++++++
 .../css/css-env/indexed-env.tentative.html    | 40 +++++++++++++
 ...seralization-round-tripping.tentative.html | 19 +++++++
 .../css-env/supports-script.tentative.html    | 22 +++++++
 .../css/css-env/syntax.tentative.html         | 57 +++++++++++++++++++
 ...env-names-override-previous.tentative.html | 17 ++++++
 18 files changed, 345 insertions(+)
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-env/at-supports.tentative.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-env/env-in-custom-properties.tentative.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-env/env-parsing.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-env/fallback-nested-var.tentative.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-env/indexed-env.tentative.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-env/seralization-round-tripping.tentative.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-env/supports-script.tentative.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-env/syntax.tentative.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-env/unknown-env-names-override-previous.tentative.txt
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-env/at-supports.tentative.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-env/env-in-custom-properties.tentative.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-env/env-parsing.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-env/fallback-nested-var.tentative.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-env/indexed-env.tentative.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-env/seralization-round-tripping.tentative.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-env/supports-script.tentative.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-env/syntax.tentative.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-env/unknown-env-names-override-previous.tentative.html

diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-env/at-supports.tentative.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/at-supports.tentative.txt
new file mode 100644
index 00000000000..7326aca0e8f
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/at-supports.tentative.txt
@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Fail
+Fail	Test that CSS env vars work with @support
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-env/env-in-custom-properties.tentative.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/env-in-custom-properties.tentative.txt
new file mode 100644
index 00000000000..ad0ff933ede
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/env-in-custom-properties.tentative.txt
@@ -0,0 +1,7 @@
+Harness status: OK
+
+Found 2 tests
+
+2 Fail
+Fail	env() is substituted into a custom property
+Fail	Substitution of unrecognized env() causes guaranteed-invalid
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-env/env-parsing.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/env-parsing.txt
new file mode 100644
index 00000000000..f09b6907f3a
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/env-parsing.txt
@@ -0,0 +1,14 @@
+Harness status: OK
+
+Found 8 tests
+
+5 Pass
+3 Fail
+Fail	e.style['width'] = "env(safe-area-inset-top)" should set the property value
+Fail	e.style['width'] = "env(safe-area-inset-top,)" should set the property value
+Fail	e.style['width'] = "env(safe-area-inset-top, )" should set the property value
+Pass	e.style['width'] = "env(safe-area-inset-top ())" should not set the property value
+Pass	e.style['width'] = "env(safe-area-inset-top () )" should not set the property value
+Pass	e.style['width'] = "env(safe-area-inset-top() )" should not set the property value
+Pass	e.style['width'] = "env(safe-area-inset-top (),)" should not set the property value
+Pass	e.style['width'] = "env(safe-area-inset-top(),)" should not set the property value
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-env/fallback-nested-var.tentative.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/fallback-nested-var.tentative.txt
new file mode 100644
index 00000000000..f5245cafaa5
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/fallback-nested-var.tentative.txt
@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Fail
+Fail	Test that nested var() fallback values work with CSS env vars
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-env/indexed-env.tentative.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/indexed-env.tentative.txt
new file mode 100644
index 00000000000..f1021850174
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/indexed-env.tentative.txt
@@ -0,0 +1,14 @@
+Harness status: OK
+
+Found 8 tests
+
+4 Pass
+4 Fail
+Pass	CSS Environment variable value "env(test1 test2, green)" must not successfully parse
+Pass	CSS Environment variable value "env(test1 10 20 test2, green)" must not successfully parse
+Pass	CSS Environment variable value "env(test 0.1, green)" must not successfully parse
+Pass	CSS Environment variable value "env(test -1, green)" must not successfully parse
+Fail	CSS Environment variable value "env(test 0, green)" must successfully parse and roundtrip
+Fail	CSS Environment variable value "env(test 0,)" must successfully parse and roundtrip
+Fail	CSS Environment variable value "env(test 0)" must successfully parse and roundtrip
+Fail	CSS Environment variable value "env(test 0 1 2 3 4, green)" must successfully parse and roundtrip
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-env/seralization-round-tripping.tentative.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/seralization-round-tripping.tentative.txt
new file mode 100644
index 00000000000..8a0ba8836e6
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/seralization-round-tripping.tentative.txt
@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Fail
+Fail	Test style seralization round tripping with CSS env vars
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-env/supports-script.tentative.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/supports-script.tentative.txt
new file mode 100644
index 00000000000..eefb89274bf
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/supports-script.tentative.txt
@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Fail
+Fail	Test that CSS env vars work with CSS.supports
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-env/syntax.tentative.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/syntax.tentative.txt
new file mode 100644
index 00000000000..e5ddc1794c4
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/syntax.tentative.txt
@@ -0,0 +1,24 @@
+Harness status: OK
+
+Found 18 tests
+
+4 Pass
+14 Fail
+Pass	 rgb(0, 128, 0)
+Fail	background-color: env(test) rgba(0, 0, 0, 0)
+Fail	background-color: ENV(test) rgba(0, 0, 0, 0)
+Fail	background-color: env(test) !important rgba(0, 0, 0, 0)
+Fail	background-color: env(test, 10px) rgba(0, 0, 0, 0)
+Fail	background-color: env(test, blue) rgb(0, 0, 255)
+Fail	background-color: env(test, env(another)) rgba(0, 0, 0, 0)
+Fail	background-color: env(test, env(another, blue)) rgb(0, 0, 255)
+Fail	background-color: env(-test) rgba(0, 0, 0, 0)
+Fail	background-color: env(--test) rgba(0, 0, 0, 0)
+Pass	background-color: env(10px) rgb(0, 128, 0)
+Pass	background-color: env(env(test)) rgb(0, 128, 0)
+Fail	background-color: env( test) rgba(0, 0, 0, 0)
+Fail	background-color: env(test ) rgba(0, 0, 0, 0)
+Fail	background-color: env( test ) rgba(0, 0, 0, 0)
+Fail	background-color: env(test /**/, blue) rgb(0, 0, 255)
+Fail	background-color: env(test, {}) rgba(0, 0, 0, 0)
+Pass	background-color: env(test, {) rgb(0, 128, 0)
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-env/unknown-env-names-override-previous.tentative.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/unknown-env-names-override-previous.tentative.txt
new file mode 100644
index 00000000000..ed8db5b5baf
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-env/unknown-env-names-override-previous.tentative.txt
@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Fail
+Fail	Test unknown env() names will override previous values
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-env/at-supports.tentative.html b/Tests/LibWeb/Text/input/wpt-import/css/css-env/at-supports.tentative.html
new file mode 100644
index 00000000000..db881e13f2e
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-env/at-supports.tentative.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <link rel="help" href="https://drafts.csswg.org/css-env-1/">
+    <title>Test that CSS env vars work with @support</title>
+    <script src="../../resources/testharness.js"></script>
+    <script src="../../resources/testharnessreport.js"></script>
+    <style>
+      @supports (background-color: env(test)) {
+        body { background-color: rgb(0, 128, 0); }
+      }
+    </style>
+  </head>
+  <body>
+    <script>
+    test(() => {
+      const style = window.getComputedStyle(document.body);
+      assert_equals(style.getPropertyValue("background-color"), "rgb(0, 128, 0)");
+    });
+    </script>
+  </body>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-env/env-in-custom-properties.tentative.html b/Tests/LibWeb/Text/input/wpt-import/css/css-env/env-in-custom-properties.tentative.html
new file mode 100644
index 00000000000..5ad93b6aae1
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-env/env-in-custom-properties.tentative.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <link rel="help" href="https://drafts.csswg.org/css-env-1/">
+    <title>Test env() will work in custom properties</title>
+    <script src="../../resources/testharness.js"></script>
+    <script src="../../resources/testharnessreport.js"></script>
+    <style>
+      #parent {
+        --var1: inherited;
+      }
+      #child {
+        --my-width: env(test, 100px);
+        width: var(--my-width);
+        --var1: env(nonexistent);
+      }
+    </style>
+  </head>
+  <body>
+    <div id="parent">
+      <div id="child"></div>
+    </div>
+    <script>
+    test(() => {
+      const style = window.getComputedStyle(child);
+      assert_equals(style.getPropertyValue("width"), "100px");
+    }, 'env() is substituted into a custom property');
+
+    test(() => {
+      const style = window.getComputedStyle(child);
+      assert_equals(style.getPropertyValue("--var1"), "");
+    }, 'Substitution of unrecognized env() causes guaranteed-invalid');
+    </script>
+  </body>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-env/env-parsing.html b/Tests/LibWeb/Text/input/wpt-import/css/css-env/env-parsing.html
new file mode 100644
index 00000000000..4694467ccf3
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-env/env-parsing.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<title>CSS Environment Variables: env() parsing</title>
+<link rel="help" href="https://drafts.csswg.org/css-env/">
+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<script src="../../css/support/parsing-testcommon.js"></script>
+<div id="target"></div>
+
+<script>
+
+test_valid_value('width', 'env(safe-area-inset-top)');
+test_valid_value('width', 'env(safe-area-inset-top,)');
+test_valid_value('width', 'env(safe-area-inset-top, )');
+
+test_invalid_value('width', 'env(safe-area-inset-top ())');
+test_invalid_value('width', 'env(safe-area-inset-top () )');
+test_invalid_value('width', 'env(safe-area-inset-top() )');
+test_invalid_value('width', 'env(safe-area-inset-top (),)');
+test_invalid_value('width', 'env(safe-area-inset-top(),)');
+
+</script>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-env/fallback-nested-var.tentative.html b/Tests/LibWeb/Text/input/wpt-import/css/css-env/fallback-nested-var.tentative.html
new file mode 100644
index 00000000000..6f610428c3b
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-env/fallback-nested-var.tentative.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <link rel="help" href="https://drafts.csswg.org/css-env-1/">
+    <title>Test that nested var() fallback values work with CSS env vars</title>
+    <script src="../../resources/testharness.js"></script>
+    <script src="../../resources/testharnessreport.js"></script>
+    <style>
+      body {
+        --main-bg-color: rgb(0, 128, 0);
+        background-color: env(test, var(--main-bg-color));
+      }
+    </style>
+  </head>
+  <body>
+    <script>
+    test(() => {
+      const style = window.getComputedStyle(document.body);
+      assert_equals(style.getPropertyValue("background-color"), "rgb(0, 128, 0)");
+    });
+    </script>
+  </body>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-env/indexed-env.tentative.html b/Tests/LibWeb/Text/input/wpt-import/css/css-env/indexed-env.tentative.html
new file mode 100644
index 00000000000..19db7303cbe
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-env/indexed-env.tentative.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <link rel="help" href="https://drafts.csswg.org/css-env-1/">
+    <title>Test CSS env vars index parsing support</title>
+    <script src="../../resources/testharness.js"></script>
+    <script src="../../resources/testharnessreport.js"></script>
+  </head>
+  <body>
+    <script>
+      let invalidValues = [
+          "env(test1 test2, green)",
+          "env(test1 10 20 test2, green)",
+          "env(test 0.1, green)",
+          "env(test -1, green)",
+      ];
+      invalidValues.forEach(val => {
+        test(() => {
+          document.body.style.top = val;
+          assert_equals(document.body.style.top, "");
+        }, `CSS Environment variable value "${val}" must not successfully parse`);
+      });
+
+      let validValues = [
+          "env(test 0, green)",
+          "env(test 0,)",
+          "env(test 0)",
+          "env(test 0 1 2 3 4, green)",
+      ];
+      validValues.forEach(val => {
+        test(() => {
+          document.body.style.top = val;
+          assert_equals(document.body.style.top, val);
+        }, `CSS Environment variable value "${val}" must successfully parse and roundtrip`);
+      });
+
+    </script>
+  </body>
+</html>
+
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-env/seralization-round-tripping.tentative.html b/Tests/LibWeb/Text/input/wpt-import/css/css-env/seralization-round-tripping.tentative.html
new file mode 100644
index 00000000000..5ac874ecc49
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-env/seralization-round-tripping.tentative.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <link rel="help" href="https://drafts.csswg.org/css-env-1/">
+    <title>Test style seralization round tripping with CSS env vars</title>
+    <script src="../../resources/testharness.js"></script>
+    <script src="../../resources/testharnessreport.js"></script>
+  </head>
+  <body>
+    <script>
+    test(() => {
+      document.body.style.top = "env(test)";
+      assert_equals(document.body.style.getPropertyValue("top"), "env(test)");
+      document.body.style.setProperty("top", "env()");
+      assert_equals(document.body.style.getPropertyValue("top"), "env(test)");
+    });
+    </script>
+  </body>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-env/supports-script.tentative.html b/Tests/LibWeb/Text/input/wpt-import/css/css-env/supports-script.tentative.html
new file mode 100644
index 00000000000..70a525d6855
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-env/supports-script.tentative.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <link rel="help" href="https://drafts.csswg.org/css-env-1/">
+    <title>Test that CSS env vars work with CSS.supports</title>
+    <script src="../../resources/testharness.js"></script>
+    <script src="../../resources/testharnessreport.js"></script>
+  </head>
+  <body>
+    <script>
+    test(() => {
+      assert_true(CSS.supports("background: env(test)"));
+      assert_true(CSS.supports("background", "env(test)"));
+      assert_true(CSS.supports("background", "env(test, 10px)"));
+      assert_true(CSS.supports("background", "foobar(env(test))"));
+      assert_false(CSS.supports("background", "env()"));
+      assert_true(CSS.supports("background", "env(test, )"));
+      assert_true(CSS.supports("background", "env(test,)"));
+    });
+    </script>
+  </body>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-env/syntax.tentative.html b/Tests/LibWeb/Text/input/wpt-import/css/css-env/syntax.tentative.html
new file mode 100644
index 00000000000..61a4fd7cca2
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-env/syntax.tentative.html
@@ -0,0 +1,57 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <link rel="help" href="https://drafts.csswg.org/css-env-1/">
+    <title>Test env() syntax</title>
+    <script src="../../resources/testharness.js"></script>
+    <script src="../../resources/testharnessreport.js"></script>
+    <style>
+      div { background-color: rgb(0, 128, 0); }
+    </style>
+  </head>
+  <body>
+    <script>
+    // This value is expected if the syntax is valid.
+    const envWorkingValue = "rgba(0, 0, 0, 0)";
+
+    // This value is expected if the syntax is invalid.
+    const pageDefaultValue = "rgb(0, 128, 0)";
+
+    // This value is used to test fallback values.
+    const blueValue = "rgb(0, 0, 255)";
+
+    const testCases = [
+      { style: "", expectedPropertyValue: pageDefaultValue },
+      { style: "background-color: env(test)", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: ENV(test)", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env(test) !important", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env(test, 10px)", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env(test, blue)", expectedPropertyValue: blueValue },
+      { style: "background-color: env(test, env(another))", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env(test, env(another, blue))", expectedPropertyValue: blueValue },
+      { style: "background-color: env(-test)", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env(--test)", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env(10px)", expectedPropertyValue: pageDefaultValue },
+      { style: "background-color: env(env(test))", expectedPropertyValue: pageDefaultValue },
+      { style: "background-color: env( test)", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env(test )", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env( test )", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env(test /**/, blue)", expectedPropertyValue: blueValue },
+      { style: "background-color: env(test, {})", expectedPropertyValue: envWorkingValue },
+      { style: "background-color: env(test, {)", expectedPropertyValue: pageDefaultValue },
+    ];
+
+    testCases.forEach((testcase) => {
+      test(() => {
+        const elem = document.createElement("div");
+        const style = window.getComputedStyle(elem);
+
+        document.body.appendChild(elem);
+        elem.style.cssText = testcase.style;
+
+        assert_equals(style.getPropertyValue("background-color"), testcase.expectedPropertyValue);
+      }, testcase.style + " " + testcase.expectedPropertyValue);
+    });
+    </script>
+  </body>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-env/unknown-env-names-override-previous.tentative.html b/Tests/LibWeb/Text/input/wpt-import/css/css-env/unknown-env-names-override-previous.tentative.html
new file mode 100644
index 00000000000..394d8dd1684
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-env/unknown-env-names-override-previous.tentative.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <link rel="help" href="https://drafts.csswg.org/css-env-1/">
+    <title>Test unknown env() names will override previous values</title>
+    <script src="../../resources/testharness.js"></script>
+    <script src="../../resources/testharnessreport.js"></script>
+  </head>
+  <body style="background-color: green; background-color: env(unknown);">
+    <script>
+    test(() => {
+      const style = window.getComputedStyle(document.body);
+      assert_equals(style.getPropertyValue("background-color"), "rgba(0, 0, 0, 0)");
+    });
+    </script>
+  </body>
+</html>