Implement test for months whitespace fix

Cargo.lock

@@ -1,7 +1,5 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
-
 [[package]]
 name = "advapi32-sys"
 version = "0.2.0"

tests/by-util/test_sort.rs

@@ -8,6 +8,11 @@ fn test_helper(file_name: &str, args: &str) {
         .stdout_is_fixture(format!("{}.expected", file_name));
 }
 
+#[test]
+fn test_months_whitespace() {
+    test_helper("months-whitespace", "-M");
+}
+
 #[test]
 fn test_multiple_decimals_general() {
     new_ucmd!()

tests/fixtures/sort/months-whitespace.expected

@@ -0,0 +1,8 @@
+
+
+JAN
+  FEb
+ apr
+ apr
+			JUNNNN
+AUG 

tests/fixtures/sort/months-whitespace.txt

@@ -0,0 +1,8 @@
+JAN
+			JUNNNN
+AUG 
+
+ apr
+ apr
+
+  FEb