Tests/Rules/AvoidTrailingWhitespace: Added test for usage of Invoke-Formatter with PSAvoidTrailingWhitespace and also checking that single-character lines that have trailing whitespace are not removed

Author: liamjpeters

Tests/Rules/AvoidTrailingWhitespace.tests.ps1

@@ -9,6 +9,9 @@ BeforeAll {
 
     $settings = @{
         IncludeRules = @($ruleName)
+        Rules = @{
+            $ruleName = @{}
+        }
     }
 }
 
@@ -34,4 +37,26 @@ Describe "AvoidTrailingWhitespace" {
         $violations = Invoke-ScriptAnalyzer -ScriptDefinition $def -Settings $settings
         Test-CorrectionExtentFromContent $def $violations 1 $Whitespace ''
     }
+
+    It 'Should be used by Invoke-Formatter, when in settings, replacing trailing <Type>' -TestCases $testCases {
+        param (
+            [string] $Whitespace
+        )
+        # Test also guards against regression where single-character lines, with trailing whitespace
+        # would be removed entirely. See issues #1757, #1992
+        $def = @"
+Function Get-Example {
+    'Example'$Whitespace
+}$Whitespace
+"@
+
+        $expected = @"
+Function Get-Example {
+    'Example'
 }
+"@
+        $formatted = Invoke-Formatter -ScriptDefinition $def -Settings $settings
+        $formatted | Should -Be $expected
+    }
+
+}