test: some simple bytecode tests

Author: nedbat

tests/test_bytecode.py

@@ -0,0 +1,49 @@
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt
+
+"""Tests for coverage.py's bytecode analysis."""
+
+from __future__ import annotations
+
+import dis
+
+from textwrap import dedent
+
+from tests.coveragetest import CoverageTest
+
+from coverage import env
+from coverage.bytecode import code_objects, op_set
+
+
+class BytecodeTest(CoverageTest):
+    """Tests for bytecode.py"""
+
+    def test_code_objects(self) -> None:
+        code = compile(
+            dedent("""\
+                def f(x):
+                    def g(y):
+                        return {z for z in range(10)}
+                    def j():
+                        return [z for z in range(10)]
+                    return g(x)
+                def h(x):
+                    return x+1
+                """),
+            "<string>",
+            "exec"
+        )
+
+        objs = list(code_objects(code))
+        assert code in objs
+
+        expected = {"<module>", "f", "g", "j", "h"}
+        if env.PYVERSION < (3, 12):
+            # Comprehensions were compiled as implicit functions in earlier
+            # versions of Python.
+            expected.update({"<setcomp>", "<listcomp>"})
+        assert {c.co_name for c in objs} == expected
+
+    def test_op_set(self) -> None:
+        opcodes = op_set("LOAD_CONST", "NON_EXISTENT_OPCODE", "RETURN_VALUE")
+        assert opcodes == {dis.opmap["LOAD_CONST"], dis.opmap["RETURN_VALUE"]}