Fix support for single mitigation (#30)

exasol/error/_parse.py

@@ -197,7 +197,11 @@ def normalize(params):
             description=None,
             internalDescription=None,
             potentialCauses=None,
-            mitigations=[m.value for m in mitigations.elts]
+            mitigations=(
+                [m.value for m in mitigations.elts]
+                if isinstance(mitigations, ast.List)
+                else [mitigations.value]
+            )
             if not isinstance(mitigations, str)
             else [mitigations],
             sourceFile=self._filename,
@@ -229,7 +233,8 @@ def parse_file(
             else stack.enter_context(open(file, "r"))
         )
         root_node = ast.parse(f.read())
-        collector = ErrorCollector(root_node, f.name)
+        name = f.name if hasattr(f, 'name') else f'<{f.__class__.__name__}>'
+        collector = ErrorCollector(root_node, name)
         collector.collect()
 
         return collector.error_definitions, collector.warnings, collector.errors

test/unit/regression_test.py

@@ -0,0 +1,46 @@
+import io
+from inspect import cleandoc
+
+from exasol.error._parse import parse_file
+from exasol.error._report import ErrorCodeDetails
+
+
+# regression test for GitHub Issue #26
+def test_single_mitigation():
+    f = io.StringIO(initial_value=cleandoc(
+        """
+        from exasol import error
+        from exasol.error import Parameter
+
+        var = input("description: ")
+
+        error1 = error.ExaError(
+            "E-TEST-1",
+            "this is an error",
+            "no mitigation available",
+            {},
+        )
+        """
+    ))
+
+    expected_definitions = [
+        ErrorCodeDetails(
+            identifier='E-TEST-1',
+            message='this is an error',
+            messagePlaceholders=[],
+            description=None,
+            internalDescription=None,
+            potentialCauses=None,
+            mitigations=['no mitigation available'],
+            sourceFile='<StringIO>',
+            sourceLine=6,
+            contextHash=None),
+    ]
+    expected_warnings = []
+    expected_errors = []
+
+    definitions, warnings, errors = parse_file(f)
+
+    assert expected_definitions == definitions
+    assert expected_warnings == warnings
+    assert expected_errors == errors