Test requirements.txt name normalization

tests/conftest.py

@@ -65,6 +65,7 @@ def testpkgs(tmp_path_factory):
             extras_require={"c": ["pkgc<0.0.3"], "b": ["pkgb"]},
         ),
         dict(name="pkge", install_requires=["pkgd[b,c]"]),
+        dict(name="pkg-F.G_H"),  # to test name normalization
     ]
 
     testpkgs_dir = tmp_path_factory.mktemp("testpkgs")

tests/test_sync.py

@@ -47,6 +47,39 @@ def test_sync(virtualenv_python, testpkgs, tmp_path):
     )
 
 
+def test_sync_normalization(virtualenv_python, testpkgs, tmp_path):
+    (tmp_path / "requirements.txt.in").write_text(
+        textwrap.dedent(
+            f"""\
+            --no-index
+            --find-links {testpkgs}
+            """
+        )
+    )
+    (tmp_path / "pyproject.toml").write_text(
+        textwrap.dedent(
+            """\
+            [project]
+            name = "theproject"
+            version = "1.0"
+            dependencies = ["pkg-F.G_H"]
+            """
+        )
+    )
+    subprocess.check_call(
+        [sys.executable, "-m", "pip_deepfreeze", "--python", virtualenv_python, "sync"],
+        cwd=tmp_path,
+    )
+    assert (tmp_path / "requirements.txt").read_text() == textwrap.dedent(
+        f"""\
+        # frozen requirements generated by pip-deepfreeze
+        --no-index
+        --find-links {testpkgs}
+        pkg-f-g-h==0.0.0
+        """
+    )
+
+
 def test_sync_no_in_req(virtualenv_python, tmp_path):
     (tmp_path / "setup.py").write_text(
         textwrap.dedent(