Add test_errorinfo. (enthought#819)

* Add `test_errorinfo`.

* Replace `_SetErrorInfo` with `SetErrorInfo`.
This allows us to remove the magic number `0` from the arguments without changing the behavior.

* Replace `from comtypes.hresult import *` with specific imports in `errorinfo.py`.

* Fix expected `__name__` of frames in `Test_ReportException.test_with_stacklevel`.

Author: junkmd

comtypes/errorinfo.py

@@ -4,7 +4,7 @@
 from typing import TYPE_CHECKING
 
 from comtypes import BSTR, COMMETHOD, GUID, HRESULT, IUnknown
-from comtypes.hresult import *
+from comtypes.hresult import DISP_E_EXCEPTION, S_OK
 
 if TYPE_CHECKING:
     from comtypes import hints  # type: ignore
@@ -109,7 +109,7 @@ def ReportError(
             ei.SetSource(
                 progid
             )  # progid for the class or application that created the error
-    _SetErrorInfo(0, ei)
+    SetErrorInfo(ei)
     return hresult
 
 

comtypes/test/test_errorinfo.py

@@ -0,0 +1,96 @@
+import unittest as ut
+
+from comtypes import errorinfo, shelllink
+from comtypes import hresult as hres
+
+
+class Test_GetErrorInfo(ut.TestCase):
+    def test_error_has_been_set(self):
+        self.assertIsNone(errorinfo.GetErrorInfo())
+        errmsg = "sample unexpected error message for tests"
+        errcode = hres.E_UNEXPECTED
+        helpcontext = 123
+        hr = errorinfo.ReportError(
+            errmsg,
+            shelllink.IShellLinkW._iid_,
+            str(shelllink.ShellLink._reg_clsid_),
+            helpfile="help.chm",
+            helpcontext=helpcontext,
+            hresult=errcode,
+        )
+        self.assertEqual(errcode, hr)
+        pei = errorinfo.GetErrorInfo()
+        self.assertIsNotNone(pei)
+        self.assertEqual(shelllink.IShellLinkW._iid_, pei.GetGUID())
+        self.assertEqual("lnkfile", pei.GetSource())
+        self.assertEqual(errmsg, pei.GetDescription())
+        self.assertEqual("help.chm", pei.GetHelpFile())
+        self.assertEqual(helpcontext, pei.GetHelpContext())
+        # Calling `GetErrorInfo` clears the error state for the thread.
+        # Therefore, `None` is returned in the second call.
+        self.assertIsNone(errorinfo.GetErrorInfo())
+
+    def test_without_optional_args(self):
+        self.assertIsNone(errorinfo.GetErrorInfo())
+        errmsg = "sample unexpected error message for tests"
+        hr = errorinfo.ReportError(errmsg, shelllink.IShellLinkW._iid_)
+        self.assertEqual(hres.DISP_E_EXCEPTION, hr)
+        pei = errorinfo.GetErrorInfo()
+        self.assertIsNotNone(pei)
+        self.assertEqual(shelllink.IShellLinkW._iid_, pei.GetGUID())
+        self.assertIsNone(pei.GetSource())
+        self.assertEqual(errmsg, pei.GetDescription())
+        self.assertIsNone(pei.GetHelpFile())
+        self.assertEqual(0, pei.GetHelpContext())
+
+    def test_error_has_not_been_set(self):
+        self.assertIsNone(errorinfo.GetErrorInfo())
+        pei = errorinfo.GetErrorInfo()
+        self.assertIsNone(pei)
+
+
+def raise_runtime_error():
+    _raise_runtime_error()
+
+
+def _raise_runtime_error():
+    raise RuntimeError("for testing")
+
+
+class Test_ReportException(ut.TestCase):
+    def test_without_stacklevel(self):
+        self.assertIsNone(errorinfo.GetErrorInfo())
+        iid = shelllink.IShellLinkW._iid_
+        try:
+            raise_runtime_error()
+        except RuntimeError:
+            hr = errorinfo.ReportException(hres.E_UNEXPECTED, iid)
+        self.assertEqual(hres.E_UNEXPECTED, hr)
+        pei = errorinfo.GetErrorInfo()
+        self.assertIsNotNone(pei)
+        self.assertEqual(shelllink.IShellLinkW._iid_, pei.GetGUID())
+        self.assertIsNone(pei.GetSource())
+        self.assertEqual("<class 'RuntimeError'>: for testing", pei.GetDescription())
+        self.assertIsNone(pei.GetHelpFile())
+        self.assertEqual(0, pei.GetHelpContext())
+        self.assertIsNone(errorinfo.GetErrorInfo())
+
+    def test_with_stacklevel(self):
+        self.assertIsNone(errorinfo.GetErrorInfo())
+        stem = "<class 'RuntimeError'>: for testing"
+        iid = shelllink.IShellLinkW._iid_
+        for slv, text in [
+            # XXX: If the codebase changes, the line where functions or
+            # methods are defined will change, meaning this test is brittle.
+            (0, f"{stem} ({__name__}, line 93)"),
+            (1, f"{stem} ({__name__}, line 53)"),
+            (2, f"{stem} ({__name__}, line 57)"),
+        ]:
+            with self.subTest(text=text):
+                try:
+                    raise_runtime_error()
+                except RuntimeError:
+                    errorinfo.ReportException(hres.E_UNEXPECTED, iid, stacklevel=slv)
+                pei = errorinfo.GetErrorInfo()
+                self.assertEqual(text, pei.GetDescription())
+                self.assertIsNone(errorinfo.GetErrorInfo())

pyproject.toml

@@ -11,7 +11,6 @@ ignore = ["E402"]
 "comtypes/_npsupport.py" = ["F401"]
 "comtypes/_vtbl.py" = ["E722"]
 "comtypes/automation.py" = ["F401", "F403", "F405"]
-"comtypes/errorinfo.py" = ["F403", "F405"]
 "comtypes/git.py" = ["F401", "F403", "F405"]
 "comtypes/util.py" = ["F403", "F405"]
 "comtypes/viewobject.py" = ["F403", "F405"]