[Project] Antichecked Exceptions

An alternative to checked exceptions that actually catches bugs and
prevents unintended exceptions from being accidentally caught/silenced.
Made for Python.

1 files changed, 126 insertions, 0 deletions

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+# Unit tests for Antichecked Exceptions for Python
+# Copyright (c) 2021 Soni L.
+#
+# Permission is hereby granted, free of charge, to any person ("You") obtaining
+# a copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation the
+# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+# sell copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# This license shall be void if You bring a copyright lawsuit, related or
+# unrelated to the Software, against any of the copyright holders.
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+from antichecked import exceptions
+
+class expect:
+    def __init__(self, exc, *, cause, context):
+        self.exc = exc
+        self.cause = cause or type(None)
+        self.context = context or type(None)
+
+    def __enter__(self):
+        pass
+
+    def __exit__(self, exc_ty, exc_val, exc_tb):
+        assert exc_ty is self.exc
+        assert type(exc_val.__cause__) is self.cause
+        assert type(exc_val.__context__) is self.context
+        return True
+
+def foo(i):
+    with exceptions(ValueError) as r:
+        try:
+            x = int(i)
+        except ValueError:
+            # re-raise ValueError from int()
+            raise r
+        else:
+            if x < 0:
+                # attempt to raise r without a context
+                # (should turn into RuntimeError, just like bare raise)
+                raise r
+            # this raises ValueError if x is not 1, and it becomes wrapped in
+            # RuntimeError
+            x, = [x]*x
+
+def test_foo():
+    # ValueError from int() passes through (re-raised), context/cause is None
+    with expect(ValueError, cause=None, context=None):
+        foo("false")
+    # ValueError from unpacking gets wrapped, cause and context are ValueError
+    with expect(RuntimeError, cause=ValueError, context=ValueError):
+        foo("10")
+    # raise r without context becomes RuntimeError
+    with expect(RuntimeError, cause=None, context=None):
+        foo("-10")
+    # "1" gets accepted and doesn't raise anything
+    foo("1")
+
+def bar():
+    with exceptions(ValueError) as r:
+        raise r
+
+def test_bar():
+    with expect(RuntimeError, cause=None, context=None):
+        bar()
+
+def fake_gen():
+    with exceptions(StopIteration) as r:
+        next(iter([]))
+
+def test_fake_gen():
+    # actual generators don't use RuntimeError but we have no way of testing that
+    with expect(RuntimeError, cause=StopIteration, context=StopIteration):
+        fake_gen()
+
+def baz(i):
+    with exceptions(ValueError) as r:
+        try:
+            x = int(i)
+        except ValueError:
+            # raise new exception with context
+            raise r(TypeError)
+        else:
+            if x < 0:
+                # raise a new ValueError
+                raise r(ValueError)
+            try:
+                x, = [x]*x
+            except ValueError as e:
+                # raise with cause
+                raise r(TypeError) from e
+
+def test_baz():
+    # ValueError from int() becomes TypeError with context
+    with expect(TypeError, cause=None, context=ValueError):
+        baz("false")
+    # raise TypeError with cause and context being ValueError
+    with expect(TypeError, cause=ValueError, context=ValueError):
+        baz("10")
+    # raise ValueError through antichecked exceptions
+    with expect(ValueError, cause=None, context=None):
+        baz("-10")
+    # "1" gets accepted and doesn't raise anything
+    baz("1")
+
+
+def test_all():
+    test_foo()
+    test_bar()
+    test_fake_gen()
+    test_baz()
+
+if __name__ == "__main__":
+    test_all()