chore(iast): fix grpc iast flaky tests (#12404)

## Description

Fix gRPC IAST flaky tests. The problem was that the failing ones were
run under `run_in_subprocess` so they were not getting the IAST context
fixture. However, the base class doesn't need client tests to run in a
subprocess anymore and removing that fixes the tests.

Also: remove setting the `DD_IAST_ENABLED` and the `_iast_enabled`
config from all tests since the fixture makes it unnecessary.

## Checklist
- [X] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

---------

Signed-off-by: Juanjo Alvarez <[email protected]>

tests/appsec/iast/test_grpc_iast.py

@@ -9,11 +9,8 @@
 from tests.contrib.grpc.common import GrpcBaseTestCase
 from tests.contrib.grpc.hello_pb2 import HelloRequest
 from tests.contrib.grpc.hello_pb2_grpc import HelloStub
-from tests.utils import TracerTestCase
-from tests.utils import flaky
 from tests.utils import override_config
 from tests.utils import override_env
-from tests.utils import override_global_config
 
 from .conftest import iast_context
 
@@ -38,28 +35,22 @@ def _check_test_range(value):
 
 
 class GrpcTestIASTCase(GrpcBaseTestCase):
-    @flaky(1735812000, reason="IAST context refactor breaks grpc. APPSEC-55239")
-    @TracerTestCase.run_in_subprocess(env_overrides=dict(DD_IAST_ENABLED="1"))
     def test_taint_iast_single(self):
-        with override_env({"DD_IAST_ENABLED": "True"}):
-            with self.override_config("grpc", dict(service_name="myclientsvc")):
-                with self.override_config("grpc_server", dict(service_name="myserversvc")):
-                    channel1 = grpc.insecure_channel("localhost:%d" % (_GRPC_PORT))
-                    stub1 = HelloStub(channel1)
-                    res = stub1.SayHello(HelloRequest(name="test"))
-                    assert hasattr(res, "message")
-                    _check_test_range(res.message)
-
-    def test_taint_iast_single_server(self):
-        with override_global_config(dict(_iast_enabled=True)):
-            with grpc.insecure_channel("localhost:%d" % (_GRPC_PORT)) as channel1:
+        with self.override_config("grpc", dict(service_name="myclientsvc")):
+            with self.override_config("grpc_server", dict(service_name="myserversvc")):
+                channel1 = grpc.insecure_channel("localhost:%d" % (_GRPC_PORT))
                 stub1 = HelloStub(channel1)
                 res = stub1.SayHello(HelloRequest(name="test"))
                 assert hasattr(res, "message")
                 _check_test_range(res.message)
 
-    @flaky(1735812000, reason="IAST context refactor breaks grpc. APPSEC-55239")
-    @TracerTestCase.run_in_subprocess(env_overrides=dict(DD_IAST_ENABLED="1"))
+    def test_taint_iast_single_server(self):
+        with grpc.insecure_channel("localhost:%d" % (_GRPC_PORT)) as channel1:
+            stub1 = HelloStub(channel1)
+            res = stub1.SayHello(HelloRequest(name="test"))
+            assert hasattr(res, "message")
+            _check_test_range(res.message)
+
     def test_taint_iast_twice(self):
         with self.override_config("grpc", dict(service_name="myclientsvc")):
             with self.override_config("grpc_server", dict(service_name="myserversvc")):
@@ -77,76 +68,67 @@ def test_taint_iast_twice_server(self):
         def callback(response):
             callback_called.set()
 
-        with override_global_config(dict(_iast_enabled=True)):
-            with grpc.insecure_channel("localhost:%d" % (_GRPC_PORT)) as channel1:
+        with grpc.insecure_channel("localhost:%d" % (_GRPC_PORT)) as channel1:
+            stub1 = HelloStub(channel1)
+            responses_iterator = stub1.SayHelloTwice(HelloRequest(name="test"))
+            responses_iterator.add_done_callback(callback)
+            for res in responses_iterator:
+                assert hasattr(res, "message")
+                _check_test_range(res.message)
+
+            callback_called.wait(timeout=1)
+
+    def test_taint_iast_repeatedly(self):
+        with self.override_config("grpc", dict(service_name="myclientsvc")):
+            with self.override_config("grpc_server", dict(service_name="myserversvc")):
+                channel1 = grpc.insecure_channel("localhost:%d" % (_GRPC_PORT))
                 stub1 = HelloStub(channel1)
-                responses_iterator = stub1.SayHelloTwice(HelloRequest(name="test"))
-                responses_iterator.add_done_callback(callback)
+                requests_iterator = iter(
+                    HelloRequest(name=name) for name in ["first", "second", "third", "fourth", "fifth"]
+                )
+                responses_iterator = stub1.SayHelloRepeatedly(requests_iterator)
                 for res in responses_iterator:
                     assert hasattr(res, "message")
                     _check_test_range(res.message)
 
-                callback_called.wait(timeout=1)
-
-    @flaky(1735812000, reason="IAST context refactor breaks grpc. APPSEC-55239")
-    @TracerTestCase.run_in_subprocess(env_overrides=dict(DD_IAST_ENABLED="1"))
-    def test_taint_iast_repeatedly(self):
-        with override_env({"DD_IAST_ENABLED": "True"}):
-            with self.override_config("grpc", dict(service_name="myclientsvc")):
-                with self.override_config("grpc_server", dict(service_name="myserversvc")):
-                    channel1 = grpc.insecure_channel("localhost:%d" % (_GRPC_PORT))
-                    stub1 = HelloStub(channel1)
-                    requests_iterator = iter(
-                        HelloRequest(name=name) for name in ["first", "second", "third", "fourth", "fifth"]
-                    )
-                    responses_iterator = stub1.SayHelloRepeatedly(requests_iterator)
-                    for res in responses_iterator:
-                        assert hasattr(res, "message")
-                        _check_test_range(res.message)
-
     def test_taint_iast_repeatedly_server(self):
         # use an event to signal when the callbacks have been called from the response
         callback_called = threading.Event()
 
         def callback(response):
             callback_called.set()
 
-        with override_global_config(dict(_iast_enabled=True)):
-            with grpc.insecure_channel("localhost:%d" % (_GRPC_PORT)) as channel1:
-                stub1 = HelloStub(channel1)
-                requests_iterator = iter(
-                    HelloRequest(name=name) for name in ["first", "second", "third", "fourth", "fifth"]
-                )
-                responses_iterator = stub1.SayHelloRepeatedly(requests_iterator)
-                responses_iterator.add_done_callback(callback)
-                for res in responses_iterator:
-                    assert hasattr(res, "message")
-                    _check_test_range(res.message)
+        with grpc.insecure_channel("localhost:%d" % (_GRPC_PORT)) as channel1:
+            stub1 = HelloStub(channel1)
+            requests_iterator = iter(
+                HelloRequest(name=name) for name in ["first", "second", "third", "fourth", "fifth"]
+            )
+            responses_iterator = stub1.SayHelloRepeatedly(requests_iterator)
+            responses_iterator.add_done_callback(callback)
+            for res in responses_iterator:
+                assert hasattr(res, "message")
+                _check_test_range(res.message)
 
-                callback_called.wait(timeout=1)
+            callback_called.wait(timeout=1)
 
-    @flaky(1735812000, reason="IAST context refactor breaks grpc. APPSEC-55239")
-    @TracerTestCase.run_in_subprocess(env_overrides=dict(DD_IAST_ENABLED="1"))
     def test_taint_iast_last(self):
-        with override_env({"DD_IAST_ENABLED": "True"}):
-            with self.override_config("grpc", dict(service_name="myclientsvc")):
-                with self.override_config("grpc_server", dict(service_name="myserversvc")):
-                    channel1 = grpc.insecure_channel("localhost:%d" % (_GRPC_PORT))
-                    stub1 = HelloStub(channel1)
-                    requests_iterator = iter(HelloRequest(name=name) for name in ["first", "second"])
-                    res = stub1.SayHelloLast(requests_iterator)
-                    assert hasattr(res, "message")
-                    _check_test_range(res.message)
-
-    def test_taint_iast_last_server(self):
-        with override_global_config(dict(_iast_enabled=True)):
-            with grpc.insecure_channel("localhost:%d" % (_GRPC_PORT)) as channel1:
+        with self.override_config("grpc", dict(service_name="myclientsvc")):
+            with self.override_config("grpc_server", dict(service_name="myserversvc")):
+                channel1 = grpc.insecure_channel("localhost:%d" % (_GRPC_PORT))
                 stub1 = HelloStub(channel1)
                 requests_iterator = iter(HelloRequest(name=name) for name in ["first", "second"])
                 res = stub1.SayHelloLast(requests_iterator)
                 assert hasattr(res, "message")
                 _check_test_range(res.message)
 
+    def test_taint_iast_last_server(self):
+        with grpc.insecure_channel("localhost:%d" % (_GRPC_PORT)) as channel1:
+            stub1 = HelloStub(channel1)
+            requests_iterator = iter(HelloRequest(name=name) for name in ["first", "second"])
+            res = stub1.SayHelloLast(requests_iterator)
+            assert hasattr(res, "message")
+            _check_test_range(res.message)
+
     def test_taint_iast_patching_import_error(self):
         with mock.patch.dict("sys.modules", {"google._upb._message": None}), override_env({"DD_IAST_ENABLED": "True"}):
             from collections import UserDict