Add regression tests for custom key bindings

Also tests capitalized key bindings, hence the need to compare case
sensitively.

test/powershell/Modules/PSReadLine/PSReadLine.Tests.ps1

@@ -20,7 +20,7 @@ Describe "PSReadLine" -tags "CI" {
 
     It "Should use Windows Bindings on Windows" -skip:(-not $IsWindows) {
         (Get-PSReadLineOption).EditMode | Should Be Windows
-        (Get-PSReadlineKeyHandler | where { $_.Key -eq "Ctrl+A" }).Function | Should Be SelectAll
+        (Get-PSReadlineKeyHandler | where { $_.Key -eq "Ctrl+a" }).Function | Should Be SelectAll
     }
 
     It "Should set the edit mode" {
@@ -31,6 +31,17 @@ Describe "PSReadLine" -tags "CI" {
         (Get-PSReadlineKeyHandler | where { $_.Key -eq "Ctrl+A" }).Function | Should Be BeginningOfLine
     }
 
+    It "Should allow custom bindings for plain keys" {
+        Set-PSReadlineKeyHandler -Key '"' -Function SelfInsert
+        (Get-PSReadLineKeyHandler | where { $_.Key -eq '"' }).Function | Should Be SelfInsert
+    }
+
+    It "Should report Capitalized bindings correctly" {
+        Set-PSReadlineOption -EditMode Emacs
+        (Get-PSReadLineKeyHandler | where { $_.Key -ceq "Alt+b" }).Function | Should Be BackwardWord
+        (Get-PSReadLineKeyHandler | where { $_.Key -ceq "Alt+B" }).Function | Should Be SelectBackwardWord
+    }
+
     AfterAll {
         Remove-Module PSReadLine