test: Add some basic tests for CFG

Makefile

@@ -4,11 +4,16 @@ PY = $(wildcard *.py)
 
 MYPY ?= mypy
 
-all : check
+all : test
 
-check : $(PY:%=%.mypy)
+typecheck : $(PY:%=%.mypy)
+
+unit:
+	pytest
+
+test: typecheck unit
 
 %.mypy : %
-	$(MYPY) --check-untyped-defs --warn-redundant-casts --warn-unused-ignores --warn-return-any $<
+	$(MYPY) --typecheck-untyped-defs --warn-redundant-casts --warn-unused-ignores --warn-return-any $<
 
-.PHONY: %.mypy check all
+.PHONY: %.mypy typecheck test unit all

fja/tests/cfl/cfg_test.py

+from ...common import Nonterminal, Terminal
+from ... import cfl
+from copy import deepcopy
+
+A = Nonterminal("A")
+B = Nonterminal("B")
+C = Nonterminal("C")
+a = Terminal("a")
+b = Terminal("b")
+
+Rules = cfl.CFG.Rules
+
+rules0: Rules = dict()
+g0 = cfl.CFG({A}, {a, b}, rules0, A)
+
+rules1: Rules = {A: {(a,), (a, A), (b, B), (b,)},
+                 B: {(b,), (b, B)}}
+g1 = cfl.CFG({A, B}, {a, b}, rules1, A)
+
+rules2: Rules = {A: {(a,), (a, A), (b, B)},
+                 B: {(b, B), ()}}
+g2 = cfl.CFG({A, B}, {a, b}, rules2, A)
+
+
+def test_empty():
+    assert g0.is_empty()
+
+
+def test_basics():
+    assert g1.init == A
+    assert g1.terminals == {a, b}
+    assert g1.nonterminals == {A, B}
+    assert g1.rules == rules1
+    collected_prods = set(g1.productions())
+    assert collected_prods == {(src, dst) for src, prods in rules1.items()
+                               for dst in prods}
+
+
+def test_generates():
+    def go(g):
+        assert g.generates("a")
+        assert g.generates("b")
+        assert g.generates("aa")
+        assert g.generates("ab")
+        assert g.generates("abbb")
+        assert g.generates("aabbb")
+        assert not g.generates("")
+        assert not g.generates("ba")
+
+    go(g1)
+    go(g2)
+
+
+def test_remove_eps():
+    g = g2.epsilon_normal_form()
+    assert g.init == g1.init
+    assert g.terminals == g1.terminals
+    assert g.nonterminals == g1.nonterminals
+    assert g.rules == g1.rules