Fixes bug in isort-assignments sorting.issue/1515/isort-assignments-sorting-bug

Fixes #1515.

Bonus: increases branch coverage of literals.py to 100%

3 files changed, 21 insertions, 16 deletions

diff --git a/isort/literal.py b/isort/literal.py
index 28e0855c..01bd05e7 100644
--- a/isort/literal.py
+++ b/isort/literal.py
@@ -21,17 +21,18 @@ type_mapping: Dict[str, Tuple[type, Callable[[Any, ISortPrettyPrinter], str]]] =
 
 
 def assignments(code: str) -> str:
-    sort_assignments = {}
+    values = {}
     for line in code.splitlines(keepends=True):
-        if line:
-            if " = " not in line:
-                raise AssignmentsFormatMismatch(code)
-            else:
-                variable_name, value = line.split(" = ", 1)
-                sort_assignments[variable_name] = value
-
-    sorted_assignments = dict(sorted(sort_assignments.items(), key=lambda item: item[1]))
-    return "".join(f"{key} = {value}" for key, value in sorted_assignments.items())
+        if not line.strip():
+            continue
+        if " = " not in line:
+            raise AssignmentsFormatMismatch(code)
+        variable_name, value = line.split(" = ", 1)
+        values[variable_name] = value
+
+    return "".join(
+        f"{variable_name} = {values[variable_name]}" for variable_name in sorted(values.keys())
+    )
 
 
 def assignment(code: str, sort_type: str, extension: str, config: Config = DEFAULT_CONFIG) -> str:
diff --git a/tests/unit/test_literal.py b/tests/unit/test_literal.py
index 0dd7458c..ee623927 100644
--- a/tests/unit/test_literal.py
+++ b/tests/unit/test_literal.py
@@ -20,7 +20,7 @@ def test_invalid_sort_type():
         isort.literal.assignment("x = [1, 2, 3", "tuple-list-not-exist", "py")
 
 
-def test_value_assignment():
+def test_value_assignment_list():
     assert isort.literal.assignment("x = ['b', 'a']", "list", "py") == "x = ['a', 'b']"
     assert (
         isort.literal.assignment("x = ['b', 'a']", "list", "py", Config(formatter="example"))
@@ -28,6 +28,10 @@ def test_value_assignment():
     )
 
 
+def test_value_assignment_assignments():
+    assert isort.literal.assignment("b = 1\na = 2\n", "assignments", "py") == "a = 2\nb = 1\n"
+
+
 def test_assignments_invalid_section():
     with pytest.raises(exceptions.AssignmentsFormatMismatch):
-        isort.literal.assignment("x++", "assignments", "py")
+        isort.literal.assignment("\n\nx = 1\nx++", "assignments", "py")
diff --git a/tests/unit/test_ticketed_features.py b/tests/unit/test_ticketed_features.py
index f952bdc5..51b13009 100644
--- a/tests/unit/test_ticketed_features.py
+++ b/tests/unit/test_ticketed_features.py
@@ -442,9 +442,9 @@ def method():
 
 
 # isort: assignments
-d = x
+d = 1
 b = 2
-a = 1
+a = 3
 
 # isort: dict
 y = {"z": "z", "b": "b", "b": "c"}""",
@@ -476,9 +476,9 @@ def method():
 
 
 # isort: assignments
-a = 1
+a = 3
 b = 2
-d = x
+d = 1
 
 # isort: dict
 y = {"b": "c", "z": "z"}"""