1 files changed, 120 insertions, 0 deletions
diff --git a/pylint/test/functional/simplifiable_if_statement.py b/pylint/test/functional/simplifiable_if_statement.py
new file mode 100644
index 0000000..48d6dbb
--- /dev/null
+++ b/pylint/test/functional/simplifiable_if_statement.py
@@ -0,0 +1,120 @@
+"""Test that some if statement tests can be simplified."""
+
+# pylint: disable=missing-docstring, invalid-name
+
+
+def test_simplifiable_1(arg):
+    # Simple test that can be replaced by bool(arg)
+    if arg: # [simplifiable-if-statement]
+        return True
+    else:
+        return False
+
+
+def test_simplifiable_2(arg, arg2):
+    # Can be reduced to bool(arg and not arg2)
+    if arg and not arg2: # [simplifiable-if-statement]
+        return True
+    else:
+        return False
+
+
+def test_simplifiable_3(arg, arg2):
+    # Can be reduced to bool(arg and not arg2)
+    if arg and not arg2: # [simplifiable-if-statement]
+        var = True
+    else:
+        var = False
+    return var
+
+
+def test_simplifiable_4(arg):
+    if arg:
+        var = True
+    else:
+        if arg == "arg1": # [simplifiable-if-statement]
+            return True
+        else:
+            return False
+    return var
+
+
+def test_not_necessarily_simplifiable_1(arg, arg2):
+    # Can be reduced to bool(not arg and not arg2) or to
+    # `not all(N)`, which is a bit harder to understand
+    # than `any(N)` when var should be False.
+    if arg or arg2:
+        var = False
+    else:
+        var = True
+    return var
+
+
+def test_not_necessarily_simplifiabile_2(arg):
+    # This could theoretically be reduced to `not arg or arg > 3`
+    # but the net result is that now the condition is harder to understand,
+    # because it requires understanding of an extra clause:
+    #   * first, there is the negation of truthness with `not arg`
+    #   * the second clause is `arg > 3`, which occurs when arg has a
+    #     a truth value, but it implies that `arg > 3` is equivalent
+    #     with `arg and arg > 3`, which means that the user must
+    #     think about this assumption when evaluating `arg > 3`.
+    #     The original form is easier to grasp.
+    if arg and arg <= 3:
+        return False
+    else:
+        return True
+
+
+def test_not_simplifiable_3(arg):
+    if arg:
+        test_not_necessarily_simplifiabile_2(arg)
+        test_not_necessarily_simplifiable_1(arg, arg)
+        return False
+    else:
+        if arg < 3:
+            test_simplifiable_3(arg, 42)
+        return True
+
+
+def test_not_simplifiable_4(arg):
+    # Not interested in multiple elifs
+    if arg == "any":
+        return True
+    elif test_not_simplifiable_3(arg) == arg:
+        return True
+    else:
+        return False
+
+
+def test_not_simplifiable_5(arg):
+    # Different actions in each branch
+    if arg == "any":
+        return True
+    else:
+        var = 42
+    return var
+
+
+def test_not_simplifiable_6(arg):
+    # Different actions in each branch
+    if arg == "any":
+        var = 42
+    else:
+        return True
+    return var
+
+def test_not_simplifiable_7(arg):
+    # Returning something different
+    if arg == "any":
+        return 4
+    else:
+        return 5
+
+
+def test_not_simplifiable_8(arg):
+    # Only one of the branch returns something boolean
+    if arg == "any":
+        return True
+    else:
+        return 0