diff --git a/tests/fixtures.py b/tests/fixtures.py
index 080add19..aa6ffac9 100644
--- a/tests/fixtures.py
+++ b/tests/fixtures.py
@@ -213,6 +213,36 @@ def setUp(self):
         build_files(EggInfoPkg.files, prefix=self.site_dir)
 
 
+class EggInfoPkgPipInstalledNoModules(OnSysPath, SiteDir):
+    files: FilesDef = {
+        "empty_egg_pkg.egg-info": {
+            "PKG-INFO": "Name: empty_egg-pkg",
+            # SOURCES.txt is made from the source archive, and contains files
+            # (setup.py) that are not present after installation.
+            "SOURCES.txt": """
+                setup.py
+                empty_egg_pkg.egg-info/PKG-INFO
+                empty_egg_pkg.egg-info/SOURCES.txt
+                empty_egg_pkg.egg-info/top_level.txt
+            """,
+            # installed-files.txt is written by pip, and is a strictly more
+            # accurate source than SOURCES.txt as to the installed contents of
+            # the package.
+            "installed-files.txt": """
+                PKG-INFO
+                SOURCES.txt
+                top_level.txt
+            """,
+            # top_level.txt correctly reflects that no modules are installed
+            "top_level.txt": b"\n",
+        },
+    }
+
+    def setUp(self):
+        super().setUp()
+        build_files(EggInfoPkgPipInstalledNoModules.files, prefix=self.site_dir)
+
+
 class EggInfoFile(OnSysPath, SiteDir):
     files: FilesDef = {
         "egginfo_file.egg-info": """
diff --git a/tests/test_api.py b/tests/test_api.py
index 504d0553..3bf4a41f 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -27,12 +27,12 @@ def suppress_known_deprecation():
 
 class APITests(
     fixtures.EggInfoPkg,
+    fixtures.EggInfoPkgPipInstalledNoModules,
     fixtures.DistInfoPkg,
     fixtures.DistInfoPkgWithDot,
     fixtures.EggInfoFile,
     unittest.TestCase,
 ):
-
     version_pattern = r'\d+\.\d+(\.\d)?'
 
     def test_retrieves_version_of_self(self):
@@ -63,15 +63,28 @@ def test_prefix_not_matched(self):
                     distribution(prefix)
 
     def test_for_top_level(self):
-        self.assertEqual(
-            distribution('egginfo-pkg').read_text('top_level.txt').strip(), 'mod'
-        )
+        tests = [
+            ('egginfo-pkg', 'mod'),
+            ('empty_egg-pkg', ''),
+        ]
+        for pkg_name, expect_content in tests:
+            with self.subTest(pkg_name):
+                self.assertEqual(
+                    distribution(pkg_name).read_text('top_level.txt').strip(),
+                    expect_content,
+                )
 
     def test_read_text(self):
-        top_level = [
-            path for path in files('egginfo-pkg') if path.name == 'top_level.txt'
-        ][0]
-        self.assertEqual(top_level.read_text(), 'mod\n')
+        tests = [
+            ('egginfo-pkg', 'mod\n'),
+            ('empty_egg-pkg', '\n'),
+        ]
+        for pkg_name, expect_content in tests:
+            with self.subTest(pkg_name):
+                top_level = [
+                    path for path in files(pkg_name) if path.name == 'top_level.txt'
+                ][0]
+                self.assertEqual(top_level.read_text(), expect_content)
 
     def test_entry_points(self):
         eps = entry_points()
@@ -171,6 +184,7 @@ def test_files_dist_info(self):
 
     def test_files_egg_info(self):
         self._test_files(files('egginfo-pkg'))
+        self._test_files(files('empty_egg-pkg'))
 
     def test_version_egg_info_file(self):
         self.assertEqual(version('egginfo-file'), '0.1')
diff --git a/tests/test_main.py b/tests/test_main.py
index f0f84983..4d28fa26 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -170,11 +170,17 @@ def test_metadata_loads_egg_info(self):
         assert meta['Description'] == 'pôrˈtend'
 
 
-class DiscoveryTests(fixtures.EggInfoPkg, fixtures.DistInfoPkg, unittest.TestCase):
+class DiscoveryTests(
+    fixtures.EggInfoPkg,
+    fixtures.EggInfoPkgPipInstalledNoModules,
+    fixtures.DistInfoPkg,
+    unittest.TestCase,
+):
     def test_package_discovery(self):
         dists = list(distributions())
         assert all(isinstance(dist, Distribution) for dist in dists)
         assert any(dist.metadata['Name'] == 'egginfo-pkg' for dist in dists)
+        assert any(dist.metadata['Name'] == 'empty_egg-pkg' for dist in dists)
         assert any(dist.metadata['Name'] == 'distinfo-pkg' for dist in dists)
 
     def test_invalid_usage(self):
@@ -304,7 +310,11 @@ def test_packages_distributions_example2(self):
 
 
 class PackagesDistributionsTest(
-    fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase
+    fixtures.EggInfoPkg,
+    fixtures.EggInfoPkgPipInstalledNoModules,
+    fixtures.OnSysPath,
+    fixtures.SiteDir,
+    unittest.TestCase,
 ):
     def test_packages_distributions_neither_toplevel_nor_files(self):
         """
@@ -322,3 +332,24 @@ def test_packages_distributions_neither_toplevel_nor_files(self):
             prefix=self.site_dir,
         )
         packages_distributions()
+
+    def test_packages_distributions_on_eggs(self):
+        """
+        Test old-style egg packages with a variation of 'top_level.txt',
+        'SOURCES.txt', and 'installed-files.txt', available.
+        """
+        distributions = packages_distributions()
+
+        def import_names_from_package(package_name):
+            return {
+                import_name
+                for import_name, package_names in distributions.items()
+                if package_name in package_names
+            }
+
+        # egginfo-pkg declares one import ('mod') via top_level.txt
+        assert import_names_from_package('egginfo-pkg') == {'mod'}
+
+        # empty_egg-pkg should not be associated with any import names
+        # (top_level.txt is empty, and installed-files.txt has no .py files)
+        assert import_names_from_package('empty_egg-pkg') == set()