adapt BDD tests for new postcode table structure

test/bdd/utils/grid.py

@@ -8,6 +8,7 @@
 A grid describing node placement in an area.
 Useful for visually describing geometries.
 """
+import re
 
 
 class Grid:
@@ -44,3 +45,28 @@ class Grid:
 
     def parse_line(self, value):
         return [self.parse_point(p) for p in value.split(',')]
+
+    def geometry_to_wkt(self, value):
+        """ Parses the given value into a geometry and returns the WKT.
+
+            The value can either be a WKT already or a geometry shortcut
+            with coordinates or grid points.
+        """
+        if re.fullmatch(r'([A-Z]+)\((.*)\)', value) is not None:
+            return value  # already a WKT
+
+        # points
+        if ',' not in value:
+            x, y = self.parse_point(value)
+            return f"POINT({x} {y})"
+
+        # linestring
+        if '(' not in value:
+            coords = ','.join(' '.join(f"{p:.7f}" for p in pt)
+                              for pt in self.parse_line(value))
+            return f"LINESTRING({coords})"
+
+        # simple polygons
+        coords = ','.join(' '.join(f"{p:.7f}" for p in pt)
+                          for pt in self.parse_line(value[1:-1]))
+        return f"POLYGON(({coords}))"