XCTest inverses "Actual" and "Expected" values

[belaspahn]

Describe the bug
'expected' and 'actual' are matched in the wrong order from the message regex matches. The colouring of red and green seem to be displayed correctly.

To Reproduce
Steps to reproduce the behavior:

1. Run a Test from within VSCode window
2. Click on a red flagged issue for any XCTAssertEqual() to unfold details
3. Notice the mislabelling of "Expected" and "Actual"

Expected behavior
To be displayed correctly

Environment

• OS: macOS 15.3.2
• Swift version: 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1)
• Visual Studio Code version: 1.98.1
• vscode-swift version: 2.0.2 (last updated 2025-03-16, 18:15:03)

Additional context
Potential location of bug:

File: /src/TestExplorer/TestParsers/XCTestOutputParser.ts

private extractDiff(message: string): TestIssueDiff | undefined {
    const regex = /\((.*)\) is not .* to \((.*)\)/ms;
    const match = message.match(regex);
    if (match && match[1] !== match[2]) {
        return {
            expected: match[1],
            actual: match[2],
        };
    }

    return undefined;
}

[plemarquand]

There is no preferred argument order for XCTestAssertEqual, so I think either interpretation is valid. While one way works for some codebases, it won't for others.

[plemarquand]

On reflection I think you're right, and it should be switched. The order of the values in the red error label on a failing assertion is inverted.

[matthewbastien]

Verified with a1a6b0f