show deselected info after collected info and before test execution

[fontealpina]

In my workflow, may be useful get the informations about deselected tests after the collected info an before the beginning of tests executed, because (especially if the test execution takes a long time), I would check if I have properly selected the test to run.
For instance, would be nice something like this:

$pytest -v -s test_try.py -m fast
============================ test session starts ============================
platform linux2 -- Python 2.7.6 -- py-1.4.26 -- pytest-2.9.1 -- /usr/bin/python
collected 4 items 
===================== 3 tests deselected by "-m 'fast'" =====================
test_try.py .

Currently this info is shown after the test execution.
I was wondering if there is an easy way to get this also before the test execution, maybe writing a plugin?

Thanks

[nicoddemus]

A plugin is possible I guess, but I wonder if it makes sense to change this behavior in pytest itself:

$pytest -v -s test_try.py -m fast
============================ test session starts ============================
platform linux2 -- Python 2.7.6 -- py-1.4.26 -- pytest-2.9.1 -- /usr/bin/python
collected 4 items (3 deselected by "-m 'fast'")
test_try.py .

[RonnyPfannschmidt]

sounds like a good idea

[fontealpina]

ok, for me this would be super.
Maybe wouldn't be better print the number of 'selected' tests instead of the 'deselected' ones?

[RonnyPfannschmidt]

if we just print the number of selected ones we also avoid the bug wrt deselection reasons

[nicoddemus]

@RonnyPfannschmidt hmm which bug do you mean?

[RonnyPfannschmidt]

#1372

[nicoddemus]

I see, thanks!

[arunksaha]

+1. A list of deselected tests would be useful.

For example, when I see

==================================================================================== 11 tests deselected ====================================================================================
========================================================================= 45 passed, 11 deselected in 35.98 seconds =========================================================================

it will be useful for me to be able to quickly find out which 11 tests were deselected.

[The-Compiler]

I don't think it's a good idea to print such a list by default. If I use -m foo or -k foo, I don't want a list of hundreds/thousands of tests I'm explicitly not interested in.

[arunksaha]

@The-Compiler Agree, listing hundreds/thousands of tests by default won't be a good idea :)

How about listing them when an additional flag, such as --list-deselected, is specified?

[nicoddemus]

I agree with @The-Compiler, if this functionality is implemented it should definitely be opt-in. 😁

[twmr]

The following patch adds the deselection count to the 'collected' line, but does not yet remove the deselection summary (==== X tests deselected ====).

WDYT should we remove this summary line if the deselection count is part of the 'collected' line?

diff --git a/_pytest/terminal.py b/_pytest/terminal.py
index 51d21cb..e5c5d9d 100644
--- a/_pytest/terminal.py
+++ b/_pytest/terminal.py
@@ -356,6 +356,8 @@ class TerminalReporter(object):
 
         errors = len(self.stats.get('error', []))
         skipped = len(self.stats.get('skipped', []))
+        deselected = len(self.stats.get('deselected', []))
+
         if final:
             line = "collected "
         else:
@@ -365,6 +367,8 @@ class TerminalReporter(object):
             line += " / %d errors" % errors
         if skipped:
             line += " / %d skipped" % skipped
+        if deselected:
+            line += " / %d deselected" % deselected
         if self.isatty:
             self.rewrite(line, bold=True, erase=True)
             if final:
@@ -372,6 +376,7 @@ class TerminalReporter(object):
         else:
             self.write_line(line)
 
+    @pytest.hookimpl(trylast=True)
     def pytest_collection_modifyitems(self):
         self.report_collect(True)