Add new test for passing with cache clear

src/python/pants/backend/python/typecheck/pyright/rules_integration_test.py

@@ -6,6 +6,8 @@
 import json
 from textwrap import dedent
 from typing import Iterable
+from pants.util.contextutil import temporary_dir
+from pants.util.dirutil import safe_rmtree
 
 import pytest
 
@@ -138,6 +140,26 @@ def test_passing(rule_runner: PythonRuleRunner) -> None:
     assert result[0].report == EMPTY_DIGEST
 
 
+def test_passing_cache_clear(rule_runner: PythonRuleRunner) -> None:
+    rule_runner.write_files({f"{PACKAGE}/f.py": GOOD_FILE, f"{PACKAGE}/BUILD": "python_sources()"})
+    with temporary_dir() as named_caches:
+        tgt = rule_runner.get_target(Address(PACKAGE, relative_file_path="f.py"))
+        result = run_pyright(rule_runner, [tgt], extra_args=[f"--named-caches-dir={named_caches}"])
+        assert len(result) == 1
+        assert result[0].exit_code == 0
+        assert "0 errors" in result[0].stdout
+        assert result[0].report == EMPTY_DIGEST
+        # Remove the cache dir and run the tests again - should yield the same result
+        safe_rmtree(named_caches)
+        # On the second run, the result should be the same as the first even though the cache directory
+        # has been deleted.
+        result = run_pyright(rule_runner, [tgt], extra_args=[f"--named-caches-dir={named_caches}"])
+        assert len(result) == 1
+        assert result[0].exit_code == 0
+        assert "0 errors" in result[0].stdout
+        assert result[0].report == EMPTY_DIGEST
+
+
 def test_failing(rule_runner: PythonRuleRunner) -> None:
     rule_runner.write_files({f"{PACKAGE}/f.py": BAD_FILE, f"{PACKAGE}/BUILD": "python_sources()"})
     tgt = rule_runner.get_target(Address(PACKAGE, relative_file_path="f.py"))