Fixed issues in the original rule, added more testing

Author: raghushantha

Rules/AvoidUsingComputerNameHardcoded.cs

@@ -16,6 +16,7 @@
 using System.ComponentModel.Composition;
 using System.Globalization;
 using System.Collections.Generic;
+using System.Linq;
 
 namespace Microsoft.Windows.PowerShell.ScriptAnalyzer.BuiltinRules
 {
@@ -49,11 +50,22 @@ public override bool ParameterCondition(CommandAst CmdAst, CommandElementAst CeA
 
                 if (String.Equals(cmdParamAst.ParameterName, "computername", StringComparison.OrdinalIgnoreCase))
                 {
-                    Ast computerNameArgument = GetComputerNameArg(CmdAst, cmdParamAst.Extent.StartOffset);
-                    List<string> localhostExceptions = new List<string>{ "localhost", ".", "::1", "127.0.0.1" };
-                    if ((null != computerNameArgument) && (!localhostExceptions.Contains(computerNameArgument.Extent.Text)))
+                    List<string> localhostRepresentations = new List<string> { "localhost", ".", "::1", "127.0.0.1" };
+                    Ast computerNameArgument = GetComputerNameArg(CmdAst, cmdParamAst.Extent.StartOffset);                                        
+
+                    if (null != computerNameArgument)
+                    {
+                        if (!localhostRepresentations.Contains(computerNameArgument.Extent.Text.ToLower()))
+                        {
+                            return computerNameArgument is ConstantExpressionAst;
+                        }
+
+                        return false;
+                    }
+                    
+                    if (null != cmdParamAst.Argument && !localhostRepresentations.Contains(cmdParamAst.Argument.ToString().Replace("\"", "").Replace("'", "").ToLower()))
                     {
-                        return cmdParamAst.Argument is ConstantExpressionAst || computerNameArgument is ConstantExpressionAst;
+                        return cmdParamAst.Argument is ConstantExpressionAst;
                     }
                 }
             }

Tests/Rules/AvoidUsingComputerNameHardcodedNoViolations.ps1

@@ -3,4 +3,8 @@ Invoke-Command -ComputerName $env:COMPUTERNAME
 Invoke-Command -ComputerName localhost
 Invoke-Command -ComputerName .
 Invoke-Command -ComputerName ::1
-Invoke-Command -ComputerName 127.0.0.1
+Invoke-Command -ComputerName 127.0.0.1
+Invoke-Command -ComputerName:'localhost'
+Invoke-Command -ComputerName:"."
+Invoke-Command -ComputerName:'::1'
+Invoke-Command -ComputerName:"127.0.0.1"