restructure project + unit tests

tests/test_anf.py

@@ -0,0 +1,90 @@
+import itertools
+
+from anf import convert
+from anf.parser import Parser, tokenize
+
+
+def parse(expr):
+    return Parser(tokenize(expr)).parse()
+
+
+def eval_poly(poly, env):
+    res = False
+    for mono in poly:
+        term = True
+        for v in mono:
+            term &= env.get(v, False)
+        res ^= term
+    return res
+
+
+def eval_expr(expr, env):
+    py = expr
+    py = py.replace("!", " not ")
+    py = py.replace("AND", " and ")
+    py = py.replace("OR", " or ")
+    py = py.replace("+", " or ")
+    py = py.replace("*", " and ")
+    return eval(py, {"__builtins__": {}}, env)
+
+
+def equivalent(expr):
+    poly = parse(expr)
+    vars_ = sorted({t for t in tokenize(expr) if t.startswith("X")})
+
+    for values in itertools.product([False, True], repeat=len(vars_)):
+        env = dict(zip(vars_, values))
+        assert eval_expr(expr, env) == eval_poly(poly, env)
+
+
+# ------------------------
+# Tests
+# ------------------------
+
+def test_basic_or():
+    assert equivalent("X1 OR X2") is None
+
+
+def test_basic_and():
+    assert equivalent("X1 AND X2") is None
+
+
+def test_not():
+    assert equivalent("!X1") is None
+
+
+def test_plus_star_syntax():
+    assert equivalent("X1 * (X2 + !X3)") is None
+
+
+def test_idempotent():
+    assert convert("X1 OR X1") == "X1"
+
+
+def test_contradiction():
+    assert convert("X1 AND !X1") == "0"
+
+
+def test_big_formula():
+    expr = (
+        "!X11 AND (!X3 AND !X4 OR X3 AND X4 OR X3 AND !X4 AND X12) OR X11 AND !X12 AND (X3 OR X4)"
+    )
+
+    expected = (
+        "1⊕X11⊕X3⊕X4⊕(X3⸱X12)⊕(X4⸱X11⸱X12)⊕(X3⸱X4⸱X11)⊕(X3⸱X4⸱X12)"
+    )
+
+    assert convert(expr) == expected
+
+
+def test_equivalence_suite():
+    formulas = [
+        "X1 OR X2",
+        "X1 AND !X2",
+        "!(X1 OR X2)",
+        "(X1 + X2) * (!X1 + X3)",
+        "!X1 AND (!X2 OR X3) OR X1 AND X2",
+    ]
+
+    for f in formulas:
+        equivalent(f)