bdd: improve assert output for API query checks

Adds wrapper function for checking address parts and
more explanation strings to asserts.

test/bdd/steps/check_functions.py

@@ -3,10 +3,35 @@ Collection of assertion functions used for the steps.
 """
 
 class Almost:
-
+    """ Compares a float value with a certain jitter.
+    """
     def __init__(self, value, offset=0.00001):
         self.value = value
         self.offset = offset
 
     def __eq__(self, other):
         return abs(other - self.value) < self.offset
+
+class Bbox:
+    """ Comparator for bounding boxes.
+    """
+    def __init__(self, bbox_string):
+        self.coord = [float(x) for x in bbox_string.split(',')]
+
+    def __contains__(self, item):
+        if isinstance(item, str):
+            item = item.split(',')
+        item = list(map(float, item))
+
+        if len(item) == 2:
+            return self.coord[0] <= item[0] <= self.coord[2] \
+                   and self.coord[1] <= item[1] <= self.coord[3]
+
+        if len(item) == 4:
+            return item[0] >= self.coord[0] and item[1] <= self.coord[1] \
+                   and item[2] >= self.coord[2] and item[3] <= self.coord[3]
+
+        raise ValueError("Not a coordinate or bbox.")
+
+    def __str__(self):
+        return str(self.coord)