From 81ae091b11f53127d52f3fd51ca2c67cd389df72 Mon Sep 17 00:00:00 2001
From: Peter Hill <zed.three@gmail.com>
Date: Mon, 23 Aug 2021 17:44:52 +0100
Subject: [PATCH] Allow last shot to work without an existing source

---
 pyxpad/pyxpad.py     | 22 +++++++++++-----------
 tests/test_pyxpad.py |  8 ++++++++
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/pyxpad/pyxpad.py b/pyxpad/pyxpad.py
index 3e86e26..eb7f1f3 100755
--- a/pyxpad/pyxpad.py
+++ b/pyxpad/pyxpad.py
@@ -728,20 +728,20 @@ def lastShot(self):
         """
         Get the latest shot number
         """
-
-        # Find an XPadSource in the list of sources
         from pyxpad.xpadsource import XPadSource
 
-        source = None
-        for _source in self.sources.sources:
-            if isinstance(_source, XPadSource):
-                source = _source
-        if source is None:
-            # None available
-            return
+        try:
+            source = self.sources.sources[0]
+        except IndexError:
+            source = XPadSource()
 
-        # Now ask for the lastshot
-        last_shot_number = source.last_shot_number
+        try:
+            last_shot_number = source.last_shot_number
+        except AttributeError:
+            self.statusbar.showMessage(
+                "Last shot number not available for {source.label}", 1500
+            )
+            return
 
         # Append the shot number to any existing shot numbers
         current_text = self.shotInput.text()
diff --git a/tests/test_pyxpad.py b/tests/test_pyxpad.py
index a1df5b6..6391e7d 100644
--- a/tests/test_pyxpad.py
+++ b/tests/test_pyxpad.py
@@ -29,6 +29,14 @@ def test_get_last_shot(mock_uda, copy_tree_data, pyxpadbot, qtbot):
     assert str(main.shotInput.text()).strip() == MOCK_LAST_SHOT
 
 
+def test_get_last_shot_no_source(mock_uda, pyxpadbot, qtbot):
+    main = pyxpadbot
+
+    main.lastShotButton.setEnabled(True)
+    qtbot.mouseClick(main.lastShotButton, QtCore.Qt.LeftButton)
+    assert str(main.shotInput.text()).strip() == MOCK_LAST_SHOT
+
+
 def test_get_available_signals(mock_uda, pyxpadbot, qtbot):
     main = pyxpadbot