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Eric Roller's blog

Saturday, January 31, 2015

XCTest: Place Error Markers in Another File

I have a XCTestCase scenario using the following methodology:

- (void)testScript {
    NSError* error = nil;
    for (NSURL *scriptURL in [self findScriptFiles]) {

        // Read the entire file.
        NSString *text = [NSString stringWithContentsOfURL:scriptURL
                encoding:NSUTF8StringEncoding error:&error];

        // Test each line.
        [text enumerateLinesUsingBlock:^(NSString *line, BOOL *stop) {

            XCTAssertTrue([self runInstruction:line]);
        }];
    }
}

This works, but I don’t like it that all error messages are placed in the testScript source code, whereas they should really be placed inline in the parsed script.

I did a bit of digging in the XCTestCase framework headers and found the solution, using recordFailureWithDescription:inFile:atLine:expected:

- (void)testScript {
    NSError* error = nil;
    for (NSURL *scriptURL in [self findScriptFiles]) {

        // Read the entire file.
        NSString *text = [NSString stringWithContentsOfURL:scriptURL
                encoding:NSUTF8StringEncoding error:&error];
        __block NSUInteger lineNum = 0;

        // Test each line.
        [text enumerateLinesUsingBlock:^(NSString *line, BOOL *stop) {

            lineNum++;

            if ([self runInstruction:line] == NO) {
                // Place the error marker in the parsed file!
                [self recordFailureWithDescription:@"Instruction failed"
                        inFile:[self sourcePathForURL:scriptURL]
                        atLine:lineNum
                        expected:YES];
            }
        }];
    }
}

NB. The scriptURL points to a file within the resources folder of the test target, i.e. not to the original script file in my Xcode project. I therefore need to locate the original script file, for instance relative to the current source file (whose name can be obtained through the __FILE__ preprocessor macro).