LibJS: Let isNaN() with no argument return true, add tests

1 files changed, 28 insertions, 0 deletions

diff --git a/Libraries/LibJS/Tests/isNaN.js b/Libraries/LibJS/Tests/isNaN.js
new file mode 100644
index 0000000000..7519b68fd2
--- /dev/null
+++ b/Libraries/LibJS/Tests/isNaN.js
@@ -0,0 +1,28 @@
+load("test-common.js");
+
+try {
+    assert(isNaN.length === 1);
+
+    assert(isNaN(0) === false);
+    assert(isNaN(42) === false);
+    assert(isNaN("") === false);
+    assert(isNaN("0") === false);
+    assert(isNaN("42") === false);
+    assert(isNaN(true) === false);
+    assert(isNaN(false) === false);
+    assert(isNaN(null) === false);
+    assert(isNaN([]) === false);
+    assert(isNaN(Infinity) === false);
+    assert(isNaN(-Infinity) === false);
+
+    assert(isNaN() === true);
+    assert(isNaN(NaN) === true);
+    assert(isNaN(undefined) === true);
+    assert(isNaN("foo") === true);
+    assert(isNaN({}) === true);
+    assert(isNaN([1, 2, 3]) === true);
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e.message);
+}