adding chap4 code

Author: noahgift

chapter4/Makefile

@@ -0,0 +1,12 @@
+install:
+	pip install --upgrade pip &&\
+		pip install -r requirements.txt
+
+test:
+	python -m pytest -vv test_hello.py
+
+
+lint:
+	pylint --disable=R,C hello.py
+
+all: install lint test

chapter4/hello.py

@@ -1,2 +1,10 @@
-def toyou():
-    return "hi"
+def toyou(x):
+    return f"hi {x}"
+
+
+def add(x):
+    return x + 1
+
+
+def subtract(x):
+    return x - 1

chapter4/requirements.txt

@@ -0,0 +1,3 @@
+pylint
+pytest
+black

chapter4/test_hello.py

@@ -0,0 +1,19 @@
+from hello import toyou, add, subtract
+
+
+def setup_function(function):
+    print(f" Running Setup: {function.__name__}")
+    function.x = 10
+
+
+def teardown_function(function):
+    print(f" Running Teardown: {function.__name__}")
+    del function.x
+
+
+### Run to see failed test
+#def test_hello_add():
+#    assert add(test_hello_add.x) == 12
+
+def test_hello_subtract():
+    assert subtract(test_hello_subtract.x) == 9

requirements.txt

@@ -3,3 +3,4 @@ pytest
 pytest-cov
 jupyter
 click
+devml