Refactor _find_caller into a public test finder utility

This moves the _find_caller utility method from rest_client into it's
own public utility so that we can use it elsewhere in Tempest, like to
uniquely identify which test case fails in a TimeoutException.

This is useful to uniquely fingerprint timeout failures with
elastic-recheck which is not always possible right now because we don't
have multi-line query support with elastic-recheck.

Related-Bug: #1315201

Change-Id: I0cef7697e36a0ecd29c2540a5c283d322b2c62b7
diff --git a/tempest/common/rest_client.py b/tempest/common/rest_client.py
index 8667445..4f1e709 100644
--- a/tempest/common/rest_client.py
+++ b/tempest/common/rest_client.py
@@ -15,7 +15,6 @@
 #    under the License.
 
 import collections
-import inspect
 import json
 from lxml import etree
 import re
@@ -24,6 +23,7 @@
 import jsonschema
 
 from tempest.common import http
+from tempest.common.utils import misc as misc_utils
 from tempest.common import xml_utils as common
 from tempest import config
 from tempest import exceptions
@@ -224,57 +224,6 @@
         versions = map(lambda x: x['id'], body)
         return resp, versions
 
-    def _find_caller(self):
-        """Find the caller class and test name.
-
-        Because we know that the interesting things that call us are
-        test_* methods, and various kinds of setUp / tearDown, we
-        can look through the call stack to find appropriate methods,
-        and the class we were in when those were called.
-        """
-        caller_name = None
-        names = []
-        frame = inspect.currentframe()
-        is_cleanup = False
-        # Start climbing the ladder until we hit a good method
-        while True:
-            try:
-                frame = frame.f_back
-                name = frame.f_code.co_name
-                names.append(name)
-                if re.search("^(test_|setUp|tearDown)", name):
-                    cname = ""
-                    if 'self' in frame.f_locals:
-                        cname = frame.f_locals['self'].__class__.__name__
-                    if 'cls' in frame.f_locals:
-                        cname = frame.f_locals['cls'].__name__
-                    caller_name = cname + ":" + name
-                    break
-                elif re.search("^_run_cleanup", name):
-                    is_cleanup = True
-                else:
-                    cname = ""
-                    if 'self' in frame.f_locals:
-                        cname = frame.f_locals['self'].__class__.__name__
-                    if 'cls' in frame.f_locals:
-                        cname = frame.f_locals['cls'].__name__
-
-                    # the fact that we are running cleanups is indicated pretty
-                    # deep in the stack, so if we see that we want to just
-                    # start looking for a real class name, and declare victory
-                    # once we do.
-                    if is_cleanup and cname:
-                        if not re.search("^RunTest", cname):
-                            caller_name = cname + ":_run_cleanups"
-                            break
-            except Exception:
-                break
-        # prevents frame leaks
-        del frame
-        if caller_name is None:
-            self.LOG.debug("Sane call name not found in %s" % names)
-        return caller_name
-
     def _get_request_id(self, resp):
         for i in ('x-openstack-request-id', 'x-compute-request-id'):
             if i in resp:
@@ -290,7 +239,7 @@
         # we're going to just provide work around on who is actually
         # providing timings by gracefully adding no content if they don't.
         # Once we're down to 1 caller, clean this up.
-        caller_name = self._find_caller()
+        caller_name = misc_utils.find_test_caller()
         if secs:
             secs = " %.3fs" % secs
         self.LOG.info(
diff --git a/tempest/common/utils/misc.py b/tempest/common/utils/misc.py
index a0b0c0a..b9f411b 100644
--- a/tempest/common/utils/misc.py
+++ b/tempest/common/utils/misc.py
@@ -13,6 +13,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import inspect
+import re
+
+from tempest.openstack.common import log as logging
+
+LOG = logging.getLogger(__name__)
+
 
 def singleton(cls):
     """Simple wrapper for classes that should only have a single instance."""
@@ -23,3 +30,55 @@
             instances[cls] = cls()
         return instances[cls]
     return getinstance
+
+
+def find_test_caller():
+    """Find the caller class and test name.
+
+    Because we know that the interesting things that call us are
+    test_* methods, and various kinds of setUp / tearDown, we
+    can look through the call stack to find appropriate methods,
+    and the class we were in when those were called.
+    """
+    caller_name = None
+    names = []
+    frame = inspect.currentframe()
+    is_cleanup = False
+    # Start climbing the ladder until we hit a good method
+    while True:
+        try:
+            frame = frame.f_back
+            name = frame.f_code.co_name
+            names.append(name)
+            if re.search("^(test_|setUp|tearDown)", name):
+                cname = ""
+                if 'self' in frame.f_locals:
+                    cname = frame.f_locals['self'].__class__.__name__
+                if 'cls' in frame.f_locals:
+                    cname = frame.f_locals['cls'].__name__
+                caller_name = cname + ":" + name
+                break
+            elif re.search("^_run_cleanup", name):
+                is_cleanup = True
+            else:
+                cname = ""
+                if 'self' in frame.f_locals:
+                    cname = frame.f_locals['self'].__class__.__name__
+                if 'cls' in frame.f_locals:
+                    cname = frame.f_locals['cls'].__name__
+
+                # the fact that we are running cleanups is indicated pretty
+                # deep in the stack, so if we see that we want to just
+                # start looking for a real class name, and declare victory
+                # once we do.
+                if is_cleanup and cname:
+                    if not re.search("^RunTest", cname):
+                        caller_name = cname + ":_run_cleanups"
+                        break
+        except Exception:
+            break
+    # prevents frame leaks
+    del frame
+    if caller_name is None:
+        LOG.debug("Sane call name not found in %s" % names)
+    return caller_name
diff --git a/tempest/tests/common/utils/test_misc.py b/tempest/tests/common/utils/test_misc.py
index b8c6184..aee9805 100644
--- a/tempest/tests/common/utils/test_misc.py
+++ b/tempest/tests/common/utils/test_misc.py
@@ -50,3 +50,39 @@
         self.assertEqual(test, test2)
         test3 = TestBar()
         self.assertNotEqual(test, test3)
+
+    def test_find_test_caller_test_case(self):
+        # Calling it from here should give us the method we're in.
+        self.assertEqual('TestMisc:test_find_test_caller_test_case',
+                         misc.find_test_caller())
+
+    def test_find_test_caller_setup_self(self):
+        def setUp(self):
+            return misc.find_test_caller()
+        self.assertEqual('TestMisc:setUp', setUp(self))
+
+    def test_find_test_caller_setup_no_self(self):
+        def setUp():
+            return misc.find_test_caller()
+        self.assertEqual(':setUp', setUp())
+
+    def test_find_test_caller_setupclass_cls(self):
+        def setUpClass(cls):  # noqa
+            return misc.find_test_caller()
+        self.assertEqual('TestMisc:setUpClass', setUpClass(self.__class__))
+
+    def test_find_test_caller_teardown_self(self):
+        def tearDown(self):
+            return misc.find_test_caller()
+        self.assertEqual('TestMisc:tearDown', tearDown(self))
+
+    def test_find_test_caller_teardown_no_self(self):
+        def tearDown():
+            return misc.find_test_caller()
+        self.assertEqual(':tearDown', tearDown())
+
+    def test_find_test_caller_teardown_class(self):
+        def tearDownClass(cls):
+            return misc.find_test_caller()
+        self.assertEqual('TestMisc:tearDownClass',
+                         tearDownClass(self.__class__))