Merge pull request #4599 from s0undt3ch/feature/skiporfail-reason

Custom reason support for "importorskip"

Author: nicoddemus

changelog/4599.feature.rst

@@ -0,0 +1,2 @@
+``pytest.importorskip`` now supports a ``reason`` parameter, which will be shown when the
+requested module cannot be imported.

src/_pytest/outcomes.py

@@ -137,10 +137,15 @@ def xfail(reason=""):
 xfail.Exception = XFailed
 
 
-def importorskip(modname, minversion=None):
-    """ return imported module if it has at least "minversion" as its
-    __version__ attribute.  If no minversion is specified the a skip
-    is only triggered if the module can not be imported.
+def importorskip(modname, minversion=None, reason=None):
+    """Imports and returns the requested module ``modname``, or skip the current test
+    if the module cannot be imported.
+
+    :param str modname: the name of the module to import
+    :param str minversion: if given, the imported module ``__version__`` attribute must be
+        at least this minimal version, otherwise the test is still skipped.
+    :param str reason: if given, this reason is shown as the message when the module
+        cannot be imported.
     """
     import warnings
 
@@ -159,7 +164,9 @@ def importorskip(modname, minversion=None):
             # Do not raise chained exception here(#1485)
             should_skip = True
     if should_skip:
-        raise Skipped("could not import %r" % (modname,), allow_module_level=True)
+        if reason is None:
+            reason = "could not import %r" % (modname,)
+        raise Skipped(reason, allow_module_level=True)
     mod = sys.modules[modname]
     if minversion is None:
         return mod

testing/test_runner.py

@@ -738,6 +738,22 @@ def test_foo():
     result.stdout.fnmatch_lines(["*collected 0 items / 1 skipped*"])
 
 
+def test_importorskip_custom_reason(testdir):
+    """make sure custom reasons are used"""
+    testdir.makepyfile(
+        """
+        import pytest
+        foobarbaz = pytest.importorskip("foobarbaz2", reason="just because")
+
+        def test_foo():
+            pass
+    """
+    )
+    result = testdir.runpytest("-ra")
+    result.stdout.fnmatch_lines(["*just because*"])
+    result.stdout.fnmatch_lines(["*collected 0 items / 1 skipped*"])
+
+
 def test_pytest_cmdline_main(testdir):
     p = testdir.makepyfile(
         """