Add FlipTexture2dEqualityComparer

[nowsprinting]

Added

FlipTexture2dEqualityComparer (optional)

FlipTexture2dEqualityComparer is a NUnit test comparer class that compares two Texture2D using FLIP.

Output error map image file if assertion fails.
Default output path is "Application.persistentDataPath/TestHelper/Screenshots/TestContext.Test.Name.diff.png".
You can specify the output directory and/or filename by constructor arguments.
Directory can also be specified by command line argument -testHelperScreenshotDirectory.

Usage:

[TestFixture]
public class MyTestClass
{
    [Test]
    public async Task MyTestMethod()
    {
        await Awaitable.EndOfFrameAsync();
        var actual = ScreenCapture.CaptureScreenshotAsTexture();
        var expected = AssetDatabase.LoadAssetAtPath<Texture2D>(ExpectedImagePath);

        var comparer = new FlipTexture2dEqualityComparer(meanErrorTolerance: 0.01f);
        Assert.That(actual, Is.EqualTo(expected).Using(comparer));
    }
}

Important

FlipTexture2dEqualityComparer is an optional functionality. To use it, you need to install the FlipBinding.CSharp NuGet package v1.0.0 or newer.
Also, add scripting define symbol ENABLE_FLIP_BINDING if not installed via OpenUPM (UnityNuGet).

[github-actions]

Code Metrics Report

	master (35345dc)	#178 (8cda137)	+/-
Coverage	79.4%	79.4%	0.0%
Code to Test Ratio	1:1.0	1:1.0	-0.1
Test Execution Time	8m8s	5m18s	-2m50s

Details

  |                     | master (35345dc) | #178 (8cda137) |  +/-   |
  |---------------------|------------------|----------------|--------|
  | Coverage            |            79.4% |          79.4% |   0.0% |
  |   Files             |               44 |             44 |      0 |
  |   Lines             |             1581 |           1581 |      0 |
  |   Covered           |             1256 |           1256 |      0 |
- | Code to Test Ratio  |            1:1.0 |          1:1.0 |   -0.1 |
  |   Code              |             2773 |           2917 |   +144 |
+ |   Test              |             2968 |           3096 |   +128 |
+ | Test Execution Time |             8m8s |          5m18s | -2m50s |

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Reported by octocov