added changelog entry

moved cache readme tests to test_cacheprovider.py

changelog/3519.feature.rst

@@ -0,0 +1 @@
+now `.pytest_cache` is created with a README.md to indicate it's usage,options etc.

src/_pytest/cacheprovider.py

@@ -15,6 +15,7 @@ import pytest
 import json
 import os
 from os.path import sep as _sep, altsep as _altsep
+from textwrap import dedent
 
 
 class Cache(object):
@@ -106,15 +107,19 @@ class Cache(object):
                 self._ensure_readme()
 
     def _ensure_readme(self):
-        content_readme = """# pytest cache directory #
 
-This directory contains data from the pytest's cache plugin, \
+        content_readme = dedent(
-which provides the `--lf` and `--ff` options, as well as the `cache` fixture.
+            """\
+        # pytest cache directory #
 
-**Do not** commit this to version control.
+        This directory contains data from the pytest's cache plugin,\
+        which provides the `--lf` and `--ff` options, as well as the `cache` fixture.
 
-See [the docs](https://docs.pytest.org/en/latest/cache.html) for more information.
+        **Do not** commit this to version control.
+
+        See [the docs](https://docs.pytest.org/en/latest/cache.html) for more information.
         """
+        )
         if self._cachedir.check(dir=True):
             readme_path = self._cachedir.join("README.md")
             if not readme_path.check(file=True):

testing/test_cacheREADME.py

@@ -1,39 +0,0 @@
-from __future__ import absolute_import, division, print_function
-import _pytest
-
-pytest_plugins = ("pytester",)
-
-
-class Helper(object):
-
-    def check_readme(self, testdir):
-        config = testdir.parseconfigure()
-        readme = config.cache._cachedir.join("README.md")
-        return readme.isfile()
-
-
-class TestReadme(Helper):
-
-    def test_readme_passed(self, testdir):
-        testdir.tmpdir.join("test_a.py").write(
-            _pytest._code.Source(
-                """
-            def test_always_passes():
-                assert 1
-        """
-            )
-        )
-        testdir.runpytest()
-        assert self.check_readme(testdir) is True
-
-    def test_readme_failed(self, testdir):
-        testdir.tmpdir.join("test_a.py").write(
-            _pytest._code.Source(
-                """
-            def test_always_passes():
-                assert 0
-        """
-            )
-        )
-        testdir.runpytest()
-        assert self.check_readme(testdir) is True

testing/test_cacheprovider.py

@@ -6,7 +6,7 @@ import pytest
 import os
 import shutil
 
-pytest_plugins = "pytester",
+pytest_plugins = ("pytester",)
 
 
 class TestNewAPI(object):
@@ -818,3 +818,31 @@ class TestNewFirst(object):
                 "*test_1/test_1.py::test_1[2*",
             ]
         )
+
+
+class TestReadme(object):
+
+    def check_readme(self, testdir):
+        config = testdir.parseconfigure()
+        readme = config.cache._cachedir.join("README.md")
+        return readme.isfile()
+
+    def test_readme_passed(self, testdir):
+        testdir.makepyfile(
+            """
+            def test_always_passes():
+                assert 1
+        """
+        )
+        testdir.runpytest()
+        assert self.check_readme(testdir) is True
+
+    def test_readme_failed(self, testdir):
+        testdir.makepyfile(
+            """
+            def test_always_passes():
+                assert 0
+        """
+        )
+        testdir.runpytest()
+        assert self.check_readme(testdir) is True