Created unit tests.

apps/cli/executables/null/setup.py

@@ -10,9 +10,9 @@ README = Path('README.md').read_text()
 # requires = [
 # ]
 
-# tests_require = [
-#     'pytest>=5.4,<6.0'
-# ]
+tests_require = [
+    'pytest>=5.4,<6.0'
+]
 setup(
     name=Path().absolute().name,
     version=VERSION,
@@ -23,7 +23,7 @@ setup(
     url='TBD',
     license="GPL",
     # install_requires=requires,
-    # tests_require=tests_require,
+    tests_require=tests_require,
     keywords=[],
     packages=['null'],
     package_dir={'':'src'},

apps/cli/executables/null/test/null_test.py

+import pytest
+import argparse
+import sys
+
+from ..src.null.null import Null
+
+parser = argparse.ArgumentParser()
+
+def test_print_error(caplog):
+    null = Null(argparse.Namespace(), True)
+    null.print_error()
+    assert 'ERROR: This is an error.' in caplog.text
+
+def test_print_greeting(caplog):
+    null = Null(argparse.Namespace(), True)
+    null.print_greeting()
+    assert 'Hello, world!' in caplog.text
+    assert 'And goodbye, world...' in caplog.text
+
+def test_exit_with_failure(caplog):
+    null = Null(argparse.Namespace(), True)
+    with pytest.raises(SystemExit) as e:
+        null.exit_with_failure()
+        assert 'Error purposefully induced. Exiting with status code -1...' in caplog.text
+        assert e.value.code == -1
+
+def test_exit_randomly(caplog):
+    null = Null(argparse.Namespace(), True)
+    with pytest.raises(SystemExit) as e:
+        null.exit_randomly()
+        assert 'Exiting with status code' in caplog.text
+        assert -50 <= e.value.code <= 50
+
+def test_take_nap(caplog):
+    null = Null(argparse.Namespace(), True)
+    null.take_nap()
+    assert 'Going to sleep...' in caplog.text
+    assert 'Waking up.' in caplog.text
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