ch17: update from book draft

17-it-generator/tree/step3/test_tree.py

@@ -0,0 +1,38 @@
+from tree import tree
+
+
+def test_1_level():
+    class One: pass
+    expected = [('One', 0)]
+    result = list(tree(One))
+    assert expected == result 
+
+
+def test_2_levels_4_leaves():
+    class Branch: pass
+    class Leaf1(Branch): pass
+    class Leaf2(Branch): pass
+    class Leaf3(Branch): pass
+    class Leaf4(Branch): pass
+    expected = [
+        ('Branch', 0),
+            ('Leaf1', 1),
+            ('Leaf2', 1),
+            ('Leaf3', 1),
+            ('Leaf4', 1),
+    ]
+    result = list(tree(Branch))
+    assert expected == result 
+
+
+def test_3_levels_1_leaf():
+    class X: pass
+    class Y(X): pass
+    class Z(Y): pass
+    expected = [
+        ('X', 0),
+            ('Y', 1),
+                ('Z', 2),
+    ]
+    result = list(tree(X))
+    assert expected == result