PY-23452: fix sys.path for runners to make same as with real runners

* Python adds script folder as sys.path[0]. Since we run helper "helpers" dir is sys.path[0]. Pop it, and testrunner will patch sys.path as it is done with command line.
* Unittest is launched as module and it adds current dir -- pycharm mimics this behaviour.

python/helpers/pycharm/_jb_runner_tools.py

@@ -362,8 +362,10 @@ def jb_start_tests():
     del sys.argv[1:]  # Remove all args
     NewTeamcityServiceMessages().message('enteredTheMatrix')
 
-    # Working dir should be on path, that is how runners work when launched from command line
-    sys.path.insert(1, os.getcwd())
+    # PyCharm helpers dir is first dir in sys.path because helper is launched.
+    # But sys.path should be same as when launched with test runner directly
+    if os.path.abspath(sys.path[0]) == os.path.abspath(os.environ["PYCHARM_HELPERS_DIR"]):
+        sys.path.pop(0)
     return namespace.path, namespace.target, additional_args
 
 

python/helpers/pycharm/_jb_unittest_runner.py

@@ -32,4 +32,6 @@ if __name__ == '__main__':
     jb_doc_args("unittests", args)
     test_runner = unittestpy.TeamcityTestRunner()
     test_runner.buffer = True
+    # Working dir should be on path, that is how unittest work when launched from command line
+    sys.path.append(os.getcwd())
     main(argv=args, module=None, testRunner=test_runner)

python/testData/testRunner/env/unit/sysPath/test_sample.py

@@ -0,0 +1,10 @@
+import unittest
+import sys
+
+print("path[0]={0}".format(sys.path[0]))
+
+
+class SampleTest(unittest.TestCase):
+    def test_true(self):
+        self.assertTrue(True)
+

python/testSrc/com/jetbrains/env/python/testing/PythonUnitTestingTest.java

@@ -31,10 +31,12 @@ import com.jetbrains.python.testing.PythonTestConfigurationsModel;
 import com.jetbrains.python.testing.universalTests.PyUniversalUnitTestConfiguration;
 import com.jetbrains.python.testing.universalTests.PyUniversalUnitTestFactory;
 import com.jetbrains.python.testing.universalTests.TestTargetType;
+import org.hamcrest.Matchers;
 import org.jetbrains.annotations.NotNull;
 import org.junit.Assert;
 import org.junit.Test;
 
+import java.io.File;
 import java.io.IOException;
 import java.util.List;
 
@@ -60,6 +62,36 @@ public final class PythonUnitTestingTest extends PyEnvTestCase {
   }
 
 
+  /**
+   * Ensure that sys.path[0] is script folder, not helpers folder
+   */
+  @Test
+  public void testSysPath() throws Exception {
+    runPythonTest(new PyUnitTestProcessWithConsoleTestTask("testRunner/env/unit/sysPath", "test_sample.py") {
+
+      @NotNull
+      @Override
+      protected PyUnitTestProcessRunner createProcessRunner() throws Exception {
+        return new PyUnitTestProcessRunner(toFullPath(myScriptName), 0);
+      }
+
+      @Override
+      protected void checkTestResults(@NotNull final PyUnitTestProcessRunner runner,
+                                      @NotNull final String stdout,
+                                      @NotNull final String stderr,
+                                      @NotNull final String all) {
+        Assert.assertEquals(runner.getFormattedTestTree(), 1, runner.getAllTestsCount());
+        myFixture.getTempDirFixture().getFile("sysPath");
+
+        final VirtualFile folderWithScript = myFixture.getTempDirFixture().getFile(".");
+        assert folderWithScript != null : "No folder for script " + myScriptName;
+        Assert.assertThat("sys.path[0] should point to folder with test, while it does not", stdout,
+                          Matchers.containsString(String.format("path[0]=%s", new File(folderWithScript.getPath()).getAbsolutePath())));
+      }
+    });
+  }
+
+
   /**
    * Make sure test rerun works when pattern is enabled (PY-23416)
    */