Introduce new pytest_report_collectionfinish hook

Fix #2622

_pytest/hookspec.py

@@ -337,7 +337,10 @@ def pytest_assertrepr_compare(config, op, left, right):
 
 
 def pytest_report_header(config, startdir):
-    """ return a string to be displayed as header info for terminal reporting.
+    """ return a string or list of strings to be displayed as header info for terminal reporting.
+
+    :param config: the pytest config object.
+    :param startdir: py.path object with the starting dir
 
     .. note::
 
@@ -347,6 +350,17 @@ def pytest_report_header(config, startdir):
     """
 
 
+def pytest_report_collectionfinish(config, startdir, items):
+    """ return a string or list of strings to be displayed after collection has finished successfully.
+
+    This strings will be displayed after the standard "collected X items" message.
+
+    :param config: the pytest config object.
+    :param startdir: py.path object with the starting dir
+    :param items: list of pytest items that are going to be executed; this list should not be modified.
+    """
+
+
 @hookspec(firstresult=True)
 def pytest_report_teststatus(report):
     """ return result-category, shortletter and verbose word for reporting.

_pytest/terminal.py

@@ -323,6 +323,9 @@ class TerminalReporter:
         self.write_line(msg)
         lines = self.config.hook.pytest_report_header(
             config=self.config, startdir=self.startdir)
+        self._write_report_lines_from_hooks(lines)
+
+    def _write_report_lines_from_hooks(self, lines):
         lines.reverse()
         for line in flatten(lines):
             self.write_line(line)
@@ -349,10 +352,9 @@ class TerminalReporter:
                     rep.toterminal(self._tw)
                 return 1
             return 0
-        if not self.showheader:
+        lines = self.config.hook.pytest_report_collectionfinish(
-            return
+            config=self.config, startdir=self.startdir, items=session.items)
-        # for i, testarg in enumerate(self.config.args):
+        self._write_report_lines_from_hooks(lines)
-        #    self.write_line("test path %d: %s" %(i+1, testarg))
 
     def _printcollecteditems(self, items):
         # to print out items and their parent collectors

changelog/2622.feature

@@ -0,0 +1,2 @@
+New ``pytest_report_collectionfinish`` hook which allows plugins to add messages to the terminal reporting after
+collection has been finished successfully.

doc/en/writing_plugins.rst

@@ -644,6 +644,7 @@ Session related reporting hooks:
 .. autofunction:: pytest_collectreport
 .. autofunction:: pytest_deselected
 .. autofunction:: pytest_report_header
+.. autofunction:: pytest_report_collectionfinish
 .. autofunction:: pytest_report_teststatus
 .. autofunction:: pytest_terminal_summary
 .. autofunction:: pytest_fixture_setup

testing/test_terminal.py

@@ -544,6 +544,23 @@ class TestTerminalFunctional(object):
         assert "===" not in s
         assert "passed" not in s
 
+    def test_report_collectionfinish_hook(self, testdir):
+        testdir.makeconftest("""
+            def pytest_report_collectionfinish(config, startdir, items):
+                return ['hello from hook: {0} items'.format(len(items))]
+        """)
+        testdir.makepyfile("""
+            import pytest
+            @pytest.mark.parametrize('i', range(3))
+            def test(i):
+                pass
+        """)
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines([
+            "collected 3 items",
+            "hello from hook: 3 items",
+        ])
+
 
 def test_fail_extra_reporting(testdir):
     testdir.makepyfile("def test_this(): assert 0")