httpserver: propagate event handler exceptions to httpserver (#64)

thrau · web-flow · commit 20e1454b473f · 2021-07-29T19:04:22.000+02:00
* httpserver: propagate event handler exceptions to httpserver

* fix import error and add check() method
diff --git a/.gitignore b/.gitignore
@@ -13,3 +13,4 @@ doc/_build/
 .tox/
 .idea/
 .python-version
+__pycache__/
diff --git a/pytest_httpserver/httpserver.py b/pytest_httpserver/httpserver.py
@@ -576,6 +576,7 @@ def __init__(self, host=DEFAULT_LISTEN_HOST, port=DEFAULT_LISTEN_PORT, ssl_conte
         self.server = None
         self.server_thread = None
         self.assertions = []
+        self.handler_errors = []
         self.log = []
         self.ordered_handlers = []
         self.oneshot_handlers = RequestHandlerList()
@@ -598,6 +599,7 @@ def clear(self):
 
         """
         self.clear_assertions()
+        self.clear_handler_errors()
         self.clear_log()
         self.clear_all_handlers()
         self.permanently_failed = False
@@ -610,6 +612,13 @@ def clear_assertions(self):
 
         self.assertions = []
 
+    def clear_handler_errors(self):
+        """
+        Clears the list of collected errors from handler invocations
+        """
+
+        self.handler_errors = []
+
     def clear_log(self):
         """
         Clears the list of log entries
@@ -893,10 +902,19 @@ def add_assertion(self, obj):
         Assertions can be added here, and when :py:meth:`check_assertions` is called,
         it will raise AssertionError for pytest with the object specified here.
 
-        :param obj: An object which will be passed to AssertionError.
+        :param obj: An AssertionError, or an object which will be passed to an AssertionError.
         """
         self.assertions.append(obj)
 
+    def check(self):
+        """
+        Raises AssertionError or Errors raised in handlers.
+
+        Runs both :py:meth:`check_assertions` and :py:meth:`check_handler_errors`
+        """
+        self.check_assertions()
+        self.check_handler_errors()
+
     def check_assertions(self):
         """
         Raise AssertionError when at least one assertion added
@@ -909,7 +927,21 @@ def check_assertions(self):
         """
 
         if self.assertions:
-            raise AssertionError(self.assertions.pop(0))
+            assertion = self.assertions.pop(0)
+            if isinstance(assertion, AssertionError):
+                raise assertion
+
+            raise AssertionError(assertion)
+
+    def check_handler_errors(self):
+        """
+        Re-Raises any errors caused in request handlers
+
+        The first error raised by a handler will be re-raised here, and then
+        removed from the list.
+        """
+        if self.handler_errors:
+            raise self.handler_errors.pop(0)
 
     def format_matchers(self) -> str:
         """
@@ -1007,7 +1039,17 @@ def dispatch(self, request: Request) -> Response:
             if not handler:
                 return self.respond_nohandler(request)
 
-        response = handler.respond(request)
+        try:
+            response = handler.respond(request)
+        except Error:
+            # don't collect package-internal errors
+            raise
+        except AssertionError as e:
+            self.add_assertion(e)
+            raise
+        except Exception as e:
+            self.handler_errors.append(e)
+            raise
 
         if response is None:
             response = Response("")
diff --git a/tests/test_handler_errors.py b/tests/test_handler_errors.py
@@ -0,0 +1,92 @@
+import pytest
+import requests
+import werkzeug
+
+from pytest_httpserver import HTTPServer
+
+
+def test_check_assertions_raises_handler_assertions(httpserver: HTTPServer):
+    def handler(_):
+        assert 1 == 2
+
+    httpserver.expect_request("/foobar").respond_with_handler(handler)
+
+    requests.get(httpserver.url_for("/foobar"))
+
+    with pytest.raises(AssertionError):
+        httpserver.check_assertions()
+
+    httpserver.check_handler_errors()
+
+
+def test_check_handler_errors_raises_handler_error(httpserver: HTTPServer):
+    def handler(_) -> werkzeug.Response:
+        raise ValueError("should be propagated")
+
+    httpserver.expect_request("/foobar").respond_with_handler(handler)
+
+    requests.get(httpserver.url_for("/foobar"))
+
+    httpserver.check_assertions()
+
+    with pytest.raises(ValueError):
+        httpserver.check_handler_errors()
+
+
+def test_check_handler_errors_correct_order(httpserver: HTTPServer):
+    def handler1(_) -> werkzeug.Response:
+        raise ValueError("should be propagated")
+
+    def handler2(_) -> werkzeug.Response:
+        raise OSError("should be propagated")
+
+    httpserver.expect_request("/foobar1").respond_with_handler(handler1)
+    httpserver.expect_request("/foobar2").respond_with_handler(handler2)
+
+    requests.get(httpserver.url_for("/foobar1"))
+    requests.get(httpserver.url_for("/foobar2"))
+
+    httpserver.check_assertions()
+
+    with pytest.raises(ValueError):
+        httpserver.check_handler_errors()
+
+    with pytest.raises(OSError):
+        httpserver.check_handler_errors()
+
+    httpserver.check_handler_errors()
+
+
+def test_missing_matcher_raises_exception(httpserver):
+    requests.get(httpserver.url_for("/foobar"))
+
+    # missing handlers should not raise handler exception here
+    httpserver.check_handler_errors()
+
+    with pytest.raises(AssertionError):
+        httpserver.check_assertions()
+
+
+def test_check_raises_errors_in_order(httpserver):
+    def handler1(_):
+        assert 1 == 2
+
+    def handler2(_):
+        pass  # does nothing
+
+    def handler3(_):
+        raise ValueError
+
+    httpserver.expect_request("/foobar1").respond_with_handler(handler1)
+    httpserver.expect_request("/foobar2").respond_with_handler(handler2)
+    httpserver.expect_request("/foobar3").respond_with_handler(handler3)
+
+    requests.get(httpserver.url_for("/foobar1"))
+    requests.get(httpserver.url_for("/foobar2"))
+    requests.get(httpserver.url_for("/foobar3"))
+
+    with pytest.raises(AssertionError):
+        httpserver.check()
+
+    with pytest.raises(ValueError):
+        httpserver.check()
