zulip package: Add test runner script.

tools/test-zulip

@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+
+from importlib import import_module
+
+import os
+import sys
+import argparse
+import unittest
+
+def main():
+    TOOLS_DIR = os.path.dirname(os.path.abspath(__file__))
+    os.chdir(os.path.dirname(TOOLS_DIR))
+
+    parser = argparse.ArgumentParser(description="Run tests for the zulip package.")
+    parser.add_argument('--coverage',
+                        nargs='?',
+                        const=True,
+                        default=False,
+                        help='compute test coverage (--coverage combine to combine with previous reports)')
+    options = parser.parse_args()
+
+    if options.coverage:
+        import coverage
+        cov = coverage.Coverage(config_file="tools/.coveragerc")
+        if options.coverage == 'combine':
+            cov.load()
+        cov.start()
+
+    # Codecov seems to work only when using loader.discover. It failed to capture line executions
+    # for functions like loader.loadTestFromModule or loader.loadTestFromNames.
+    test_suites = unittest.defaultTestLoader.discover('zulip')
+    suite = unittest.TestSuite(test_suites)
+    runner = unittest.TextTestRunner(verbosity=2)
+    result = runner.run(suite)
+    if result.failures or result.errors:
+        sys.exit(1)
+
+    if not result.failures and options.coverage:
+        cov.stop()
+        cov.data_suffix = False  # Disable suffix so that filename is .coverage
+        cov.save()
+        cov.html_report()
+        print("HTML report saved in directory 'htmlcov'.")
+
+
+if __name__ == '__main__':
+    main()