macOS: add test cases for ScriptKeyEventCommand

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

macos/Sources/Features/AppleScript/ScriptKeyEventCommand.swift

@@ -11,12 +11,6 @@ final class ScriptKeyEventCommand: NSScriptCommand {
     override func performDefaultImplementation() -> Any? {
         guard NSApp.validateScript(command: self) else { return nil }
 
-        guard let keyName = directParameter as? String else {
-            scriptErrorNumber = errAEParamMissed
-            scriptErrorString = "Missing key name."
-            return nil
-        }
-
         guard let terminal = evaluatedArguments?["terminal"] as? ScriptTerminal else {
             scriptErrorNumber = errAEParamMissed
             scriptErrorString = "Missing terminal target."
@@ -35,10 +29,61 @@ final class ScriptKeyEventCommand: NSScriptCommand {
             return nil
         }
 
-        guard let key = Ghostty.Input.Key(rawValue: keyName) else {
+        let keyEvent: Ghostty.Input.KeyEvent
+        do {
+            keyEvent = try Self.parse(
+                directParameter: directParameter,
+                evaluatedArguments: evaluatedArguments)
+        } catch ArgumentError.missingKey {
+            scriptErrorNumber = errAEParamMissed
+            scriptErrorString = "Missing key name."
+            return nil
+        } catch let ArgumentError.unknownKey(keyName) {
             scriptErrorNumber = errAECoercionFail
             scriptErrorString = "Unknown key name: \(keyName)"
             return nil
+        } catch let ArgumentError.unknownModifiers(modsString) {
+            scriptErrorNumber = errAECoercionFail
+            scriptErrorString = "Unknown modifier in: \(modsString)"
+            return nil
+        } catch {
+            scriptErrorNumber = errAEEventFailed
+            scriptErrorString = "Invalid key event."
+            return nil
+        }
+
+        surface.sendKeyEvent(keyEvent)
+
+        return nil
+    }
+}
+
+extension ScriptKeyEventCommand {
+    enum ArgumentError: Error, Equatable {
+        case missingKey
+        case unknownKey(String)
+        case unknownModifiers(String)
+    }
+
+    /// Parse the scripting arguments for `send key` into the key event to
+    /// deliver to the surface.
+    ///
+    /// - Parameters:
+    ///   - directParameter: The command's direct parameter (the key name).
+    ///   - evaluatedArguments: The command's evaluated arguments.
+    ///   - translationMods: Maps the event's modifiers to the subset that
+    ///     participates in text translation for the target surface.
+    static func parse(
+        directParameter: Any?,
+        evaluatedArguments: [String: Any]?,
+        translationMods: (Ghostty.Input.Mods) -> Ghostty.Input.Mods = { $0 },
+    ) throws -> Ghostty.Input.KeyEvent {
+        guard let keyName = directParameter as? String else {
+            throw ArgumentError.missingKey
+        }
+
+        guard let key = Ghostty.Input.Key(rawValue: keyName) else {
+            throw ArgumentError.unknownKey(keyName)
         }
 
         let action: Ghostty.Input.Action
@@ -55,22 +100,17 @@ final class ScriptKeyEventCommand: NSScriptCommand {
         let mods: Ghostty.Input.Mods
         if let modsString = evaluatedArguments?["modifiers"] as? String {
             guard let parsed = Ghostty.Input.Mods(scriptModifiers: modsString) else {
-                scriptErrorNumber = errAECoercionFail
-                scriptErrorString = "Unknown modifier in: \(modsString)"
-                return nil
+                throw ArgumentError.unknownModifiers(modsString)
             }
             mods = parsed
         } else {
             mods = []
         }
 
-        let keyEvent = Ghostty.Input.KeyEvent(
+        return Ghostty.Input.KeyEvent(
             key: key,
             action: action,
-            mods: mods
+            mods: mods,
         )
-        surface.sendKeyEvent(keyEvent)
-
-        return nil
     }
 }