fix style

Author: ofek

tests/test_pytest_cov.py

@@ -1761,7 +1761,8 @@ def bad_init():
     monkeypatch.setattr(sys, 'stderr', buff)
     monkeypatch.setitem(os.environ, 'COV_CORE_SOURCE', 'foobar')
     exec(payload)
-    assert buff.getvalue() == '''pytest-cov: Failed to setup subprocess coverage. Environ: {'COV_CORE_SOURCE': 'foobar'} Exception: SpecificError()
+    assert buff.getvalue() == '''\
+pytest-cov: Failed to setup subprocess coverage. Environ: {'COV_CORE_SOURCE': 'foobar'} Exception: SpecificError()
 '''