Add the ability to get the current script or project path when using the new test runner

[alextekartik]

http://stackoverflow.com/questions/30214563/get-current-script-path-or-current-project-path-using-new-test-runner
I am porting old vm unittest files using the new test package. Some relies on input files in sub directories of my test folder. Before I was using Platform.script to find the location of such files. This works fine when using

$ dart test/my_test.dart

However using

$ pub run test

this is now pointing to a temp folder (tmp/dart_test_xxxx/runInIsolate.dart). I am unable to locate my test input files anymore. I cannot rely on the current path as I might run the test from a different working directory.

Is there a way to find the location of my_test.dart (or event the project root path), from which I could derive the locations of my files?

[nex3]

This is the sort of thing that should be exposed through the API (#48).

[jmesserly]

/sub ... I'm having the same problem (also covered in #123). Our existing tests use Platform.script to load data, making hard to migrate to test runner.

Anecdotally: most packages I've worked on with VM tests end up using data files.

Anyway, I'm guessing I can work around this with dart:mirrors ... instead of Platform.script, find the script's library URI via mirrors.

[enyo]

Is there a simple hack/workaround for this, that we can use until it is implemented? (Apart from setting an environment variable)

[alextekartik]

I use the following ugly workaround (cross posted on SO) that gets me the directory name of the current test script if I'm running it directly or with pub run test. It will definitely break if anything in the implementation changes but I needed this desperately...

library test_utils.test_script_dir;

import 'dart:io';
import 'package:path/path.dart';

// temp workaround using test package
String get testScriptDir {
  String scriptFilePath = Platform.script.toFilePath();
  print(scriptFilePath);
  if (scriptFilePath.endsWith("runInIsolate.dart")) {

    // Let's look for this line:
    // import "file:///path_to_my_test/test_test.dart" as test;

    String importLineBegin = 'import "file://';
    String importLineEnd = '" as test;';
    int importLineBeginLength = importLineBegin.length;

    String scriptContent = new File.fromUri(Platform.script).readAsStringSync();

    int beginIndex = scriptContent.indexOf(importLineBegin);
    if (beginIndex > -1) {
      int endIndex = scriptContent.indexOf(importLineEnd, beginIndex + importLineBeginLength);
      if (endIndex > -1) {
        scriptFilePath = scriptContent.substring(beginIndex + importLineBegin.length, endIndex);
      }
    }
  }
  return dirname(scriptFilePath);
}

[jmesserly]

fyi, I got it working with something a bit simpler:
https://github.com/dart-lang/dev_compiler/blob/master/test/test_util.dart

import 'dart:mirrors';
import 'package:path/path.dart' as path;

final String testDirectory =
    path.dirname((reflectClass(_TestUtils).owner as LibraryMirror).uri.path);

class _TestUtils {}

Basically, get your own library through mirrors and grab the URI path.

[munificent]

If you don't want to make a fake class, you can also do:

currentMirrorSystem().findLibrary(#your_library).uri.path);

[srawlins]

Is this a bug/feature of pub run? Should there be a sister issue over at dart-lang/pub?

[nex3]

No, if anything, it's an issue with the core libraries. The forthcoming resource/package-spec stuff should solve it, though.