Fix false positives for hyphenated functions in `function-calc-no-uns…

…paced-operator` (#5636)

Co-authored-by: Masafumi Koba <473530+ybiquitous@users.noreply.github.com>

lib/rules/function-calc-no-unspaced-operator/__tests__/index.js

@@ -87,6 +87,10 @@ testRule({
 			code: 'a { top: calc(\t+1px)}',
 			description: 'tab before sign at start',
 		},
+		{
+			code: 'a { top: calc(100% - --my-custom-function(1rem)); }',
+			description: 'custom function with hyphens in name',
+		},
 		{
 			code: 'a { top: calc(-$x - 2rem); }',
 			description: 'postcss-simple-vars and SCSS variable syntax',
@@ -100,7 +104,7 @@ testRule({
 			description: 'postcss-simple-vars and SCSS variable with hyphens',
 		},
 		{
-			code: 'a { top: calc(2rem + @fh+d*sf-as); }',
+			code: 'a { top: calc(2rem + @fh+dsf-as); }',
 			description: 'Less variable with symbols',
 		},
 		{
@@ -154,6 +158,15 @@ testRule({
 	],
 
 	reject: [
+		{
+			code: 'a { top: calc(2px+1px) }',
+			fixed: 'a { top: calc(2px + 1px) }',
+			description: 'no space before or after operator',
+			warnings: [
+				{ message: messages.expectedBefore('+'), line: 1, column: 18 },
+				{ message: messages.expectedAfter('+'), line: 1, column: 19 },
+			],
+		},
 		{
 			code: 'a { top: calc(1px +\t-1px)}',
 			fixed: 'a { top: calc(1px + -1px)}',