Add tests

Author: JukkaL

mypy/test/testgraph.py

@@ -8,7 +8,7 @@
 from mypy.build import BuildManager, BuildSourceSet, State, order_ascc, sorted_components
 from mypy.errors import Errors
 from mypy.fscache import FileSystemCache
-from mypy.graph_utils import strongly_connected_components, topsort
+from mypy.graph_utils import strongly_connected_components, topsort, topsort2
 from mypy.modulefinder import SearchPaths
 from mypy.options import Options
 from mypy.plugin import Plugin
@@ -18,14 +18,77 @@
 
 
 class GraphSuite(Suite):
+    def test_topsort_empty(self) -> None:
+        data: dict[AbstractSet[str], set[AbstractSet[str]]] = {}
+        assert_equal(list(topsort2(data)), [])
+
     def test_topsort(self) -> None:
-        a = frozenset({"A"})
-        b = frozenset({"B"})
-        c = frozenset({"C"})
-        d = frozenset({"D"})
-        data: dict[AbstractSet[str], set[AbstractSet[str]]] = {a: {b, c}, b: {d}, c: {d}}
-        res = list(topsort(data))
-        assert_equal(res, [{d}, {b, c}, {a}])
+        for topsort_func in [topsort, topsort2]:
+            a = frozenset({"A"})
+            b = frozenset({"B"})
+            c = frozenset({"C"})
+            d = frozenset({"D"})
+            data: dict[AbstractSet[str], set[AbstractSet[str]]] = {a: {b, c}, b: {d}, c: {d}}
+            res = list(topsort_func(data))
+            assert_equal(res, [{d}, {b, c}, {a}])
+
+    def test_topsort_orphan(self) -> None:
+        for topsort_func in [topsort, topsort2]:
+            a = frozenset({"A"})
+            b = frozenset({"B"})
+            data: dict[AbstractSet[str], set[AbstractSet[str]]] = {a: {b}}
+            res = list(topsort_func(data))
+            assert_equal(res, [{b}, {a}])
+
+    def test_topsort_independent(self) -> None:
+        for topsort_func in [topsort, topsort2]:
+            a = frozenset({"A"})
+            b = frozenset({"B"})
+            c = frozenset({"C"})
+            data: dict[AbstractSet[str], set[AbstractSet[str]]] = {a: set(), b: set(), c: set()}
+            res = list(topsort_func(data))
+            assert_equal(res, [{a, b, c}])
+
+    def test_topsort_linear_chain(self) -> None:
+        for topsort_func in [topsort, topsort2]:
+            a = frozenset({"A"})
+            b = frozenset({"B"})
+            c = frozenset({"C"})
+            d = frozenset({"D"})
+            data: dict[AbstractSet[str], set[AbstractSet[str]]] = {
+                a: {b},
+                b: {c},
+                c: {d},
+                d: set(),
+            }
+            res = list(topsort_func(data))
+            assert_equal(res, [{d}, {c}, {b}, {a}])
+
+    def test_topsort_self_dependency(self) -> None:
+        for topsort_func in [topsort, topsort2]:
+            a = frozenset({"A"})
+            b = frozenset({"B"})
+            data: dict[AbstractSet[str], set[AbstractSet[str]]] = {a: {a, b}, b: set()}
+            res = list(topsort_func(data))
+            assert_equal(res, [{b}, {a}])
+
+    def test_topsort_orphan_diamond(self) -> None:
+        for topsort_func in [topsort, topsort2]:
+            a = frozenset({"A"})
+            b = frozenset({"B"})
+            c = frozenset({"C"})
+            # B and C are orphans -- they appear only in values, not as keys.
+            data: dict[AbstractSet[str], set[AbstractSet[str]]] = {a: {b, c}}
+            res = list(topsort_func(data))
+            assert_equal(res, [{b, c}, {a}])
+
+    def test_topsort_cycle(self) -> None:
+        for topsort_func in [topsort, topsort2]:
+            a = frozenset({"A"})
+            b = frozenset({"B"})
+            data: dict[AbstractSet[str], set[AbstractSet[str]]] = {a: {b}, b: {a}}
+            with self.assertRaises(AssertionError):
+                list(topsort_func(data))
 
     def test_scc(self) -> None:
         vertices = {"A", "B", "C", "D"}