minor #10098 Documented the catchExceptions() method (javiereguiluz)

This PR was merged into the 3.4 branch.

Discussion
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Documented the catchExceptions() method

Fixes #8427.

Commits
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b4fd044 Documented the catchExceptions() method

Author: javiereguiluz

testing.rst

@@ -521,6 +521,19 @@ will no longer be followed::
 
     $client->followRedirects(false);
 
+Reporting Exceptions
+~~~~~~~~~~~~~~~~~~~~
+
+.. versionadded:: 3.4
+    The ``catchExceptions()`` method was introduced in Symfony 3.4.
+
+Debugging exceptions in functional tests may be difficult because by default
+they are caught and you need to look at the logs to see which exception was
+thrown. Disabling catching of exceptions in the test client allows the exception
+to be reported by PHPUnit::
+
+    $client->catchExceptions(false);
+
 .. index::
    single: Tests; Crawler