Refs #18920 Fix bug in Peak

The detPos was not being cleared properly when setting QLab.

Framework/DataObjects/src/Peak.cpp

@@ -531,6 +531,7 @@ void Peak::setQLabFrame(const Mantid::Kernel::V3D &QLabFrame,
                         boost::optional<double> detectorDistance) {
   // Clear out the detector = we can't know them
   m_detectorID = -1;
+  detPos = V3D();
   m_det = IDetector_sptr();
   m_row = -1;
   m_col = -1;

Framework/DataObjects/test/PeakTest.h

@@ -264,6 +264,18 @@ public:
     TS_ASSERT_EQUALS(qLab, qSampleRotated);
   }
 
+  void test_getQLabFrame() {
+      Instrument_sptr inst =
+          ComponentCreationHelper::createTestInstrumentRectangular2(1, 10);
+      Peak p(inst, 0, 1.5);
+      p.setQLabFrame(V3D(1, 1, 1));
+      auto q = p.getQLabFrame();
+      // should be the same
+      TS_ASSERT_DELTA(q[0], 1, 1e-5);
+      TS_ASSERT_DELTA(q[1], 1, 1e-5);
+      TS_ASSERT_DELTA(q[2], 1, 1e-5);
+  }
+
   //------------------------------------------------------------------------------------
   /** Can't have Q = 0,0,0 or 0 in the Z direction when creating */
   void test_setQLabFrame_ThrowsIfQIsNull() {

Framework/PythonInterface/test/python/mantid/api/IPeaksWorkspaceTest.py

@@ -70,9 +70,10 @@ class IPeaksWorkspaceTest(unittest.TestCase):
             p.setQLabFrame(V3D(1,1,1))
         except Exception:
             self.fail("Tried setQLabFrame with one V3D argument")
-        self.assertAlmostEquals( p.getQLabFrame().X(), -1.4976057446828845, places=10)
-        self.assertAlmostEquals( p.getQLabFrame().Y(), 0.059904229787315376, places=10)
-        self.assertAlmostEquals( p.getQLabFrame().Z(), 1.4400957702126842, places=10)
+
+        self.assertAlmostEquals( p.getQLabFrame().X(), 1.0, places=10)
+        self.assertAlmostEquals( p.getQLabFrame().Y(), 1.0, places=10)
+        self.assertAlmostEquals( p.getQLabFrame().Z(), 1.0, places=10)
         
         try:
             p.setQLabFrame(V3D(1,1,1), 1)
@@ -85,13 +86,15 @@ class IPeaksWorkspaceTest(unittest.TestCase):
     def test_peak_setQSampleFrame(self):
         pws = WorkspaceCreationHelper.createPeaksWorkspace(1, True)
         p = pws.getPeak(0)
+
         try:
             p.setQSampleFrame(V3D(1,1,1))
         except Exception:
             self.fail("Tried setQSampleFrame with one V3D argument")
-        self.assertAlmostEquals( p.getQSampleFrame().X(), -1.4976057446828845, places=10)
-        self.assertAlmostEquals( p.getQSampleFrame().Y(), 0.059904229787315376, places=10)
-        self.assertAlmostEquals( p.getQSampleFrame().Z(), 1.4400957702126842, places=10)
+
+        self.assertAlmostEquals( p.getQSampleFrame().X(), 1.0, places=10)
+        self.assertAlmostEquals( p.getQSampleFrame().Y(), 1.0, places=10)
+        self.assertAlmostEquals( p.getQSampleFrame().Z(), 1.0, places=10)
         
         try:
             p.setQSampleFrame(V3D(1,1,1), 1)