Fix aggregate execution error message

oec/interface.py

@@ -13,10 +13,15 @@ logger = logging.getLogger(__name__)
 
 class ExecuteError(Exception):
     def __init__(self, errors, responses):
-        if len(errors) == 1:
-            message = str(errors[0])
-        else:
-            message = f'{len(errors)} occurred'
+        if not errors:
+            raise ValueError('Errors required')
+
+        message = str(errors[0]) or repr(errors[0])
+
+        if len(errors) == 2:
+            message += ' and 1 other error'
+        elif len(errors) > 2:
+            message += f' and {len(errors) - 1} other errors'
 
         super().__init__(message)
 

tests/test_interface.py

@@ -1,7 +1,7 @@
 import unittest
 from unittest.mock import Mock, patch
 
-from coax import ReadAddressCounterHi, ReadAddressCounterLo, ProtocolError
+from coax import ReadAddressCounterHi, ReadAddressCounterLo, ProtocolError, ReceiveTimeout, ReceiveError
 
 import context
 
@@ -105,3 +105,24 @@ class InterfaceWrapperExecuteTestCase(unittest.TestCase):
         self.assertIsInstance(error.errors[0], ProtocolError)
 
         self.assertEqual(len(error.responses), 2)
+
+class ExecuteErrorTestCase(unittest.TestCase):
+    def test_single_str_error(self):
+        error = ExecuteError([ReceiveError('ReceiveErrorMessage')], [])
+
+        self.assertEqual(str(error), 'ReceiveErrorMessage')
+
+    def test_single_repr_error(self):
+        error = ExecuteError([ReceiveTimeout()], [])
+
+        self.assertEqual(str(error), 'ReceiveTimeout()')
+
+    def test_multiple_errors_first_str_error(self):
+        error = ExecuteError([ReceiveError('ReceiveErrorMessage'), ReceiveTimeout()], [])
+
+        self.assertEqual(str(error), 'ReceiveErrorMessage and 1 other error')
+
+    def test_multiple_errors_first_repr_error(self):
+        error = ExecuteError([ReceiveTimeout(), ReceiveError('ReceiveErrorMessage')], [])
+
+        self.assertEqual(str(error), 'ReceiveTimeout() and 1 other error')