Update --collect-only to display test descriptions when ran in verbose mode.

changelog/4371.feature.rst

@@ -0,0 +1 @@
+Updated the ``--collect-only`` option to display test descriptions when ran using ``--verbose``.

src/_pytest/terminal.py

@@ -611,6 +611,10 @@ class TerminalReporter(object):
                     continue
                 indent = (len(stack) - 1) * "  "
                 self._tw.line("%s%s" % (indent, col))
+                if self.config.option.verbose >= 1:
+                    if hasattr(col, "_obj") and col._obj.__doc__:
+                        for line in col._obj.__doc__.strip().splitlines():
+                            self._tw.line("%s%s" % (indent + "  ", line.strip()))
 
     @pytest.hookimpl(hookwrapper=True)
     def pytest_sessionfinish(self, exitstatus):

testing/test_terminal.py

@@ -276,6 +276,18 @@ class TestCollectonly(object):
         result = testdir.runpytest("--collect-only", "-rs")
         result.stdout.fnmatch_lines(["*ERROR collecting*"])
 
+    def test_collectonly_display_test_description(self, testdir):
+        testdir.makepyfile(
+            """
+            def test_with_description():
+                \""" This test has a description.
+                \"""
+                assert True
+        """
+        )
+        result = testdir.runpytest("--collect-only", "--verbose")
+        result.stdout.fnmatch_lines(["    This test has a description."])
+
     def test_collectonly_failed_module(self, testdir):
         testdir.makepyfile("""raise ValueError(0)""")
         result = testdir.runpytest("--collect-only")