Add empty test case when no test cases exist to ensure pytest exit code 0

Author: LuKrO2011

src/pynguin/testcase/export.py

@@ -290,6 +290,15 @@ def to_module(self) -> tuple[ast.Module, bool]:
             )
             import_nodes.append(sut_import)
 
+            # Create a single empty test case to ensure pytest returns exit code 0
+            empty_test = PyTestChromosomeToAstVisitor.__create_function_node(
+                "empty",
+                [ast.Pass()],
+                with_self_arg=False,
+                is_failing=False,
+            )
+            functions.append(empty_test)
+
         return ast.Module(body=import_nodes + functions, type_ignores=[]), coverage_by_import_only
 
 

tests/testcase/export/test_export.py

@@ -531,7 +531,7 @@ def test_import_export_no_xfail(
 
 
 def test_coverage_by_import_only(tmp_path: Path) -> None:
-    """When no test cases exist, SUT is imported with coverage comment and noqa."""
+    """When no test cases exist, SUT is imported with coverage comment and an empty test."""
     sut_module_name = "tests.fixtures.accessibles.accessible"
     visitor = export.PyTestChromosomeToAstVisitor(sut_module_name=sut_module_name)
 
@@ -552,3 +552,5 @@ def test_coverage_by_import_only(tmp_path: Path) -> None:
     assert "# Importing this module achieves coverage." in content
     assert "# noqa: F401" in content
     assert "import tests.fixtures.accessibles.accessible" in content
+    assert "def test_empty():" in content
+    assert "    pass" in content