Implement --setup-plan option

_pytest/main.py

@@ -50,6 +50,9 @@ def pytest_addoption(parser):
                help="load configuration from `file` instead of trying to locate one of the implicit configuration files.")
     group.addoption('--setuponly', '--setup-only', action="store_true",
                help="only setup fixtures, don't execute the tests.")
+    group.addoption('--setupplan', '--setup-plan', action="store_true",
+               help="show what fixtures and tests would be executed but don't"
+                    " execute anything.")
 
     group = parser.getgroup("collect", "collection")
     group.addoption('--collectonly', '--collect-only', action="store_true",

_pytest/python.py

@@ -2459,7 +2459,8 @@ class FixtureDef:
             # even if finalization fails, we invalidate
             # the cached fixture value
             if hasattr(self, "cached_result"):
-                if self._fixturemanager.config.option.setuponly:
+                config = self._fixturemanager.config
+                if config.option.setuponly or config.option.setupplan:
                     self._log_fixture_stack('TEARDOWN')
                     if hasattr(self, "cached_param"):
                         del self.cached_param
@@ -2507,10 +2508,14 @@ class FixtureDef:
                     fixturefunc = fixturefunc.__get__(request.instance)
 
         try:
+            config = request.config
+            if config.option.setupplan:
+                result = None
+            else:
                 result = call_fixture_func(fixturefunc, request, kwargs)
+            if config.option.setuponly or config.option.setupplan:
                 # We want to access the params of ids if they exist also in during
                 # the finish() method.
-            if self._fixturemanager.config.option.setuponly:
                 if hasattr(request, 'param'):
                     if self.ids:
                         ind = self.params.index(request.param)

_pytest/runner.py

@@ -73,7 +73,7 @@ def runtestprotocol(item, log=True, nextitem=None):
     rep = call_and_report(item, "setup", log)
     reports = [rep]
     if rep.passed:
-        if item.config.option.setuponly:
+        if item.config.option.setuponly or item.config.option.setupplan:
             show_test_item(item)
         else:
             reports.append(call_and_report(item, "call", log))

testing/python/setup_only.py

@@ -1,4 +1,12 @@
-def test_show_only_active_fixtures(testdir):
+import pytest
+
+
+@pytest.fixture(params=['--setup-only', '--setup-plan'], scope='module')
+def mode(request):
+    return request.param
+
+
+def test_show_only_active_fixtures(testdir, mode):
     p = testdir.makepyfile('''
         import pytest
         @pytest.fixture
@@ -11,7 +19,7 @@ def test_show_only_active_fixtures(testdir):
             pass
     ''')
 
-    result = testdir.runpytest("--setup-only", p)
+    result = testdir.runpytest(mode, p)
     assert result.ret == 0
 
     result.stdout.fnmatch_lines([
@@ -22,7 +30,7 @@ def test_show_only_active_fixtures(testdir):
     assert "_arg0" not in result.stdout.str()
 
 
-def test_show_different_scopes(testdir):
+def test_show_different_scopes(testdir, mode):
     p = testdir.makepyfile('''
         import pytest
         @pytest.fixture
@@ -35,7 +43,7 @@ def test_show_different_scopes(testdir):
             pass
     ''')
 
-    result = testdir.runpytest("--setup-only", p)
+    result = testdir.runpytest(mode, p)
     assert result.ret == 0
 
     result.stdout.fnmatch_lines([
@@ -47,7 +55,7 @@ def test_show_different_scopes(testdir):
     ])
 
 
-def test_show_nested_fixtures(testdir):
+def test_show_nested_fixtures(testdir, mode):
     testdir.makeconftest('''
         import pytest
         @pytest.fixture(scope='session')
@@ -63,7 +71,7 @@ def test_show_nested_fixtures(testdir):
             pass
     ''')
 
-    result = testdir.runpytest("--setup-only", p)
+    result = testdir.runpytest(mode, p)
     assert result.ret == 0
 
     result.stdout.fnmatch_lines([
@@ -75,7 +83,7 @@ def test_show_nested_fixtures(testdir):
     ])
 
 
-def test_show_fixtures_with_autouse(testdir):
+def test_show_fixtures_with_autouse(testdir, mode):
     p = testdir.makepyfile('''
         import pytest
         @pytest.fixture
@@ -88,7 +96,7 @@ def test_show_fixtures_with_autouse(testdir):
             pass
     ''')
 
-    result = testdir.runpytest("--setup-only", p)
+    result = testdir.runpytest(mode, p)
     assert result.ret == 0
 
     result.stdout.fnmatch_lines([
@@ -98,7 +106,7 @@ def test_show_fixtures_with_autouse(testdir):
     ])
 
 
-def test_show_fixtures_with_parameters(testdir):
+def test_show_fixtures_with_parameters(testdir, mode):
     testdir.makeconftest('''
         import pytest
         @pytest.fixture(scope='session', params=['foo', 'bar'])
@@ -114,7 +122,7 @@ def test_show_fixtures_with_parameters(testdir):
             pass
     ''')
 
-    result = testdir.runpytest("--setup-only", p)
+    result = testdir.runpytest(mode, p)
     assert result.ret == 0
 
     result.stdout.fnmatch_lines([
@@ -125,7 +133,7 @@ def test_show_fixtures_with_parameters(testdir):
     ])
 
 
-def test_show_fixtures_with_parameter_ids(testdir):
+def test_show_fixtures_with_parameter_ids(testdir, mode):
     testdir.makeconftest('''
         import pytest
         @pytest.fixture(
@@ -142,7 +150,7 @@ def test_show_fixtures_with_parameter_ids(testdir):
             pass
     ''')
 
-    result = testdir.runpytest("--setup-only", p)
+    result = testdir.runpytest(mode, p)
     assert result.ret == 0
 
     result.stdout.fnmatch_lines([

testing/python/setup_plan.py

@@ -0,0 +1,18 @@
+def test_show_fixtures_and_test(testdir):
+    p = testdir.makepyfile('''
+        import pytest
+        @pytest.fixture
+        def arg():
+            assert False
+        def test_arg(arg):
+            assert False
+    ''')
+
+    result = testdir.runpytest("--setup-plan", p)
+    assert result.ret == 0
+
+    result.stdout.fnmatch_lines([
+        '*SETUP    F arg*',
+        '*test_arg (fixtures used: arg)',
+        '*TEARDOWN F arg*',
+    ])