refs #8951. Params should be mandatory for algorithm.

Since this algorithm could be used for workspaces in any units. Selecting a default step-size is bad, because for say TOF workspaces, 0.1 is a very very small step.

Code/Mantid/Framework/PythonInterface/plugins/algorithms/Stitch1DMany.py

@@ -32,7 +32,7 @@ def PyInit(self):
 
         self.declareProperty(FloatArrayProperty(name="StartOverlaps", values=[]), doc="Overlap in Q.")
         self.declareProperty(FloatArrayProperty(name="EndOverlaps", values=[]), doc="End overlap in Q.")
-        self.declareProperty(FloatArrayProperty(name="Params", values=[0.1]), doc="Rebinning Parameters. See Rebin for format.")
+        self.declareProperty(FloatArrayProperty(name="Params", validator=FloatArrayMandatoryValidator()), doc="Rebinning Parameters. See Rebin for format.")
         self.declareProperty(name="ScaleRHSWorkspace", defaultValue=True, doc="Scaling either with respect to workspace 1 or workspace 2.")
         self.declareProperty(name="UseManualScaleFactor", defaultValue=False, doc="True to use a provided value for the scale factor.")
         self.declareProperty(name="ManualScaleFactor", defaultValue=1.0, doc="Provided value for the scale factor.")

Code/Mantid/Framework/PythonInterface/test/python/plugins/algorithms/Stitch1DManyTest.py

@@ -58,6 +58,13 @@ def test_stitch_throws_with_wrong_number_of_End_overlaps(self):
             self.fail("Two end overlaps, but only two workspaces. Should have thrown.")
         except RuntimeError:
             pass
+
+    def test_stich_throws_if_no_params(self):
+        try:
+            stitched = Stitch1DMany(InputWorkspaces='a, b')
+            self.fail("No Params given. Should have thrown.")
+        except RuntimeError:
+            pass
 
     #Cross-check that the result of using Stitch1DMany with two workspaces is the same as using Stitch1D.