1 files changed, 82 insertions, 0 deletions
diff --git a/tests/languages/helpers_test.py b/tests/languages/helpers_test.py
new file mode 100644
index 0000000..c52e947
--- /dev/null
+++ b/tests/languages/helpers_test.py
@@ -0,0 +1,82 @@
+import multiprocessing
+import os
+import sys
+from unittest import mock
+
+import pytest
+
+import pre_commit.constants as C
+from pre_commit.languages import helpers
+from pre_commit.prefix import Prefix
+from pre_commit.util import CalledProcessError
+from testing.auto_namedtuple import auto_namedtuple
+
+
+def test_basic_get_default_version():
+    assert helpers.basic_get_default_version() == C.DEFAULT
+
+
+def test_basic_healthy():
+    assert helpers.basic_healthy(Prefix('.'), 'default') is True
+
+
+def test_failed_setup_command_does_not_unicode_error():
+    script = (
+        'import sys\n'
+        "getattr(sys.stderr, 'buffer', sys.stderr).write(b'\\x81\\xfe')\n"
+        'exit(1)\n'
+    )
+
+    # an assertion that this does not raise `UnicodeError`
+    with pytest.raises(CalledProcessError):
+        helpers.run_setup_cmd(Prefix('.'), (sys.executable, '-c', script))
+
+
+def test_assert_no_additional_deps():
+    with pytest.raises(AssertionError) as excinfo:
+        helpers.assert_no_additional_deps('lang', ['hmmm'])
+    msg, = excinfo.value.args
+    assert msg == (
+        'For now, pre-commit does not support additional_dependencies for lang'
+    )
+
+
+SERIAL_FALSE = auto_namedtuple(require_serial=False)
+SERIAL_TRUE = auto_namedtuple(require_serial=True)
+
+
+def test_target_concurrency_normal():
+    with mock.patch.object(multiprocessing, 'cpu_count', return_value=123):
+        with mock.patch.dict(os.environ, {}, clear=True):
+            assert helpers.target_concurrency(SERIAL_FALSE) == 123
+
+
+def test_target_concurrency_cpu_count_require_serial_true():
+    with mock.patch.dict(os.environ, {}, clear=True):
+        assert helpers.target_concurrency(SERIAL_TRUE) == 1
+
+
+def test_target_concurrency_testing_env_var():
+    with mock.patch.dict(
+            os.environ, {'PRE_COMMIT_NO_CONCURRENCY': '1'}, clear=True,
+    ):
+        assert helpers.target_concurrency(SERIAL_FALSE) == 1
+
+
+def test_target_concurrency_on_travis():
+    with mock.patch.dict(os.environ, {'TRAVIS': '1'}, clear=True):
+        assert helpers.target_concurrency(SERIAL_FALSE) == 2
+
+
+def test_target_concurrency_cpu_count_not_implemented():
+    with mock.patch.object(
+            multiprocessing, 'cpu_count', side_effect=NotImplementedError,
+    ):
+        with mock.patch.dict(os.environ, {}, clear=True):
+            assert helpers.target_concurrency(SERIAL_FALSE) == 1
+
+
+def test_shuffled_is_deterministic():
+    seq = [str(i) for i in range(10)]
+    expected = ['3', '7', '8', '2', '4', '6', '5', '1', '0', '9']
+    assert helpers._shuffled(seq) == expected