Ignore spaces in assert message tests (#11478)

* Update assert message formatting

* Add space

* Add space to assert

* Only one space

* Remove a space

* Revert to before

* see

* fix

Co-authored-by: Ofek Lev <ofekmeister@gmail.com>

datadog_checks_base/tests/stubs/test_aggregator_no_duplicate.py

@@ -1,6 +1,8 @@
 # (C) Datadog, Inc. 2018-present
 # All rights reserved
 # Licensed under a 3-clause BSD style license (see LICENSE)
+from textwrap import dedent
+
 import pytest
 
 from datadog_checks.base import AgentCheck
@@ -15,24 +17,23 @@ def test_assert_no_duplicate_message(aggregator):
     check.gauge('check.metric.no_dup1', 5, tags=['aa'])
     check.gauge('check.metric.no_dup2', 6, tags=['aa'])
 
-    actual_msg = ""
+    actual_msg = "  "
     try:
         aggregator.assert_no_duplicate_metrics()
     except AssertionError as e:
-        actual_msg = str(e)
+        actual_msg += str(e).split("assert")[0].lstrip()
+    actual_msg = dedent(actual_msg)
 
     expected_msg = '''
 Duplicate metrics found:
-  - check.metric.dup1
-      MetricStub(name='check.metric.dup1', type=0, value=1.0, tags=['aa'], hostname='', device=None, flush_first_value=False)
-      MetricStub(name='check.metric.dup1', type=0, value=2.0, tags=['aa'], hostname='', device=None, flush_first_value=False)
-  - check.metric.dup2
-      MetricStub(name='check.metric.dup2', type=0, value=3.0, tags=['aa'], hostname='', device=None, flush_first_value=False)
-      MetricStub(name='check.metric.dup2', type=0, value=4.0, tags=['aa'], hostname='', device=None, flush_first_value=False)
+- check.metric.dup1
+    MetricStub(name='check.metric.dup1', type=0, value=1.0, tags=['aa'], hostname='', device=None, flush_first_value=False)
+    MetricStub(name='check.metric.dup1', type=0, value=2.0, tags=['aa'], hostname='', device=None, flush_first_value=False)
+- check.metric.dup2
+    MetricStub(name='check.metric.dup2', type=0, value=3.0, tags=['aa'], hostname='', device=None, flush_first_value=False)
+    MetricStub(name='check.metric.dup2', type=0, value=4.0, tags=['aa'], hostname='', device=None, flush_first_value=False)
 '''  # noqa: E501
-    print("\n===\n{}\n===\n".format(expected_msg.strip()))
-    print("\n===\n{}\n===\n".format(actual_msg.strip()))
-    assert expected_msg.strip() == actual_msg.split("assert")[0].strip()
+    assert expected_msg.strip() == actual_msg.strip()
 
 
 @pytest.mark.parametrize(