[PATCH 1/2] KVM test: Do a better job at handling kvm module failures

[Lucas Meneghel Rodrigues <lmr@redhat.com>]

Developers might want to use the KVM test to verify changes
only on their own local qemu source directory and will use the
'localsrc' install mode on the KVM test control file, and
provide 'load_modules': 'no' option on the params dict inside
the kvm control file. However, that option is not documented and
defaults to 'yes',  and when the code to load kvm modules can't
find a built kvm.ko module inside the source dir, an unhandled
error exception (totally unhelpful) will be thrown.

This patch makes the test throw a much more helpful error message,
helping the developer to figure out what is wrong and fix the
problem.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
---
 client/tests/kvm/kvm_install.py |   14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/client/tests/kvm/kvm_install.py b/client/tests/kvm/kvm_install.py
index 10ed7da..7118357 100755
--- a/client/tests/kvm/kvm_install.py
+++ b/client/tests/kvm/kvm_install.py
@@ -30,15 +30,21 @@ def load_kvm_modules(module_dir):
     logging.info("Loading new KVM modules...")
     kvm_module_path = None
     kvm_vendor_module_path = None
+    # Search for the built KVM modules
     for folder, subdirs, files in os.walk(module_dir):
         if "kvm.ko" in files:
             kvm_module_path = os.path.join(folder, "kvm.ko")
             kvm_vendor_module_path = os.path.join(folder, "kvm-%s.ko" % vendor)
     abort = False
-    if not os.path.isfile(kvm_module_path):
-        logging.error("Could not find KVM module that was supposed to be"
-                      " built on the source dir")
-        abort = True
+    if not kvm_module_path:
+        logging.error("Need a directory containing both kernel module and "
+                      "userspace sources.")
+        logging.error("If you are trying to build only KVM userspace and use "
+                      "the KVM modules you have already loaded, put "
+                      "'load_modules': 'no' on the control file 'params' "
+                      "dictionary.")
+        raise error.TestError("Could not find a built kvm.ko module on the "
+                              "source dir.")
     elif not os.path.isfile(kvm_vendor_module_path):
         logging.error("Could not find KVM (%s) module that was supposed to be"
                       " built on the source dir", vendor)
-- 
1.6.2.5