Fix test's perspective comparison to accept scientific notation.

This fixes the compareWithPerspective comparison function in
transform-interpolation-001.html to accept values with scientific
notation (such as numbers very close to zero).

It also fixes the comparison function to handle errors better so that
failures are reported more clearly.

(I want to do this here because the following patch would otherwise
add two more of these failures, for the CSS transitions at time 0
cases.)

Bug: 897358
Change-Id: Id1ecde987eb0ba9d0d00b6da030d74a689c1e502
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3199697
Commit-Queue: David Baron <[email protected]>
Reviewed-by: Kevin Ellis <[email protected]>
Cr-Commit-Position: refs/heads/main@{#927399}

Author: dbaron

css/css-transforms/animation/transform-interpolation-001.html

@@ -45,12 +45,27 @@
 // everything to two decimal places, which isn't OK for the matrices
 // that result from large perspective values.
 const compareWithPerspective = (actual, expected) => {
-  const matrixRegExp = /^matrix3d\(((?:(?:[-0-9.]+), ){15}(?:[-0-9.]+))\)$/;
-  const actualArray = actual.match(matrixRegExp)[1].split(", ").map(Number);
-  const expectedArray = expected.match(matrixRegExp)[1].split(", ").map(Number);
+  // TODO: This RegExp should be more precise to capture only what is a
+  // valid float, and this code should be merged with other code doing
+  // the same thing, e.g., RoundMatrix in
+  // web-animations/animation-model/animation-types/property-list.js .
+  const matrixRegExp = /^matrix3d\(((?:(?:[-0-9.e]+), ){15}(?:[-0-9.]+))\)$/;
+  const actualMatch = actual.match(matrixRegExp);
+  const expectedMatch = expected.match(matrixRegExp);
+  assert_not_equals(actualMatch, null, `${actual} should be a matrix`);
+  assert_not_equals(expectedMatch, null, `${expected} should be a matrix`);
+  if (actualMatch === null || expectedMatch === null) {
+    return;
+  }
+  const actualArray = actualMatch[1].split(", ").map(Number);
+  const expectedArray = expectedMatch[1].split(", ").map(Number);
   assert_equals(actualArray.length, 16);
   assert_equals(expectedArray.length, 16);
 
+  if (actualArray.length != expectedArray.length) {
+    return;
+  }
+
   for (let i in actualArray) {
     const error = Math.abs((actualArray[i] - expectedArray[i])) /
                   Math.max(1e-6,