Tweak UseConsistentWhitespace formatting rule to exclude first unary operator when being used in argument (#949)

* exclude unary operator form UseConsistentWhitespace rule

* fix failing test by being more precise about the use case of the unary operator enhancement

* add test and docs

* tweak fix to only apply to first argument

* Fix accidental space in test expectation

Author: bergmeister

RuleDocumentation/UseConsistentWhitespace.md

@@ -38,7 +38,7 @@ Checks if there is space between a keyword and its corresponding open parenthesi
 
 #### CheckOperator: bool (Default value is `$true`)
 
-Checks if a binary operator is surrounded on both sides by a space. E.g. `$x = 1`.
+Checks if a binary or unary operator is surrounded on both sides by a space. E.g. `$x = 1`.
 
 #### CheckSeparator: bool (Default value is `$true`)
 

Rules/UseConsistentWhitespace.cs

@@ -307,6 +307,14 @@ private IEnumerable<DiagnosticRecord> FindOperatorViolations(TokenOperations tok
                     continue;
                 }
 
+                // exclude unary operator for cases like $foo.bar(-$Var)
+                if (TokenTraits.HasTrait(tokenNode.Value.Kind, TokenFlags.UnaryOperator) &&
+                    tokenNode.Previous.Value.Kind == TokenKind.LParen &&
+                    tokenNode.Next.Value.Kind == TokenKind.Variable)
+                {
+                    continue;
+                }
+
                 var hasWhitespaceBefore = IsPreviousTokenOnSameLineAndApartByWhitespace(tokenNode);
                 var hasWhitespaceAfter = tokenNode.Next.Value.Kind == TokenKind.NewLine
                             || IsPreviousTokenOnSameLineAndApartByWhitespace(tokenNode.Next);

Tests/Engine/InvokeFormatter.tests.ps1

@@ -30,6 +30,15 @@ function foo {
 
             Invoke-Formatter $def $settings | Should -Be $expected
         }
+
+        It "Should not expand unary operators when being used as a single negative argument" {
+            $script = '$foo.bar(-$a)' 
+            Invoke-Formatter '$foo.bar(-$a)' -Settings CodeFormatting | Should -Be $script
+        }
+
+        It "Should expand unary operators when not being used as a single negative argument" {
+            Invoke-Formatter '$foo.bar(-$a+$b+$c)' -Settings CodeFormatting | Should -Be '$foo.bar(-$a + $b + $c)' 
+        }
     }
 
     Context "When a range is given" {