ReventWorkload: State detection fixes

- Corrected code highlighting and phase names in documentation
- Fixed check_states paremeter not being honoured
- Moved state dependencies check to happen earlier in execution
  and to be a user facing error

wlauto/common/android/workload.py

@@ -240,7 +240,7 @@ class ApkWorkload(Workload):
         context.add_classifiers(apk_version=self.apk_version)
 
         if self.launch_main:
-            self.launch_package() # launch default activity without intent data
+            self.launch_package()  # launch default activity without intent data
         self.device.execute('am kill-all')  # kill all *background* activities
         self.device.clear_logcat()
 
@@ -439,6 +439,7 @@ AndroidBenchmark = ApkWorkload  # backward compatibility
 
 
 class ReventWorkload(Workload):
+    # pylint: disable=attribute-defined-outside-init
 
     def __init__(self, device, _call_super=True, **kwargs):
         if _call_super:
@@ -452,7 +453,9 @@ class ReventWorkload(Workload):
         self.on_device_setup_revent = None
         self.on_device_run_revent = None
         self.statedefs_dir = None
-        self.check_states = None
+
+        if self.check_states:
+            state_detector.check_match_state_dependencies()
 
     def setup(self, context):
         self.revent_setup_file = context.resolver.get(ReventFile(self, 'setup'))

wlauto/utils/statedetect.py

@@ -40,6 +40,8 @@ try:
 except ImportError:
     imutils = None
 
+from wlauto.exceptions import HostError
+
 
 class StateDefinitionError(RuntimeError):
     pass
@@ -58,10 +60,14 @@ def auto_canny(image, sigma=0.33):
     return edged
 
 
+def check_match_state_dependencies():
+    if np is None or cv2 is None or imutils is None:
+        raise HostError("State detection requires numpy, opencv (cv2) and imutils.")
+
+
 def match_state(screenshot_file, defpath, state_definitions):  # pylint: disable=too-many-locals
     # check dependencies
-    if np is None or cv2 is None or imutils is None:
-        raise RuntimeError("State detection requires numpy, opencv (cv2) and imutils.")
+    check_match_state_dependencies()
 
     # check if file exists, then load screenshot into opencv and create edge map
     if not os.path.isfile(screenshot_file):