Add Simctl that wraps xcrun simctl calls

Sources/XcodeSimulatorKit/Simctl.swift

@@ -0,0 +1,28 @@
+import Foundation
+import Basic
+import SPMUtility
+
+struct Simctl {
+    enum Error: Swift.Error {
+        case listDevices(errorOutput: String)
+    }
+
+    static func listDevices() throws -> Data {
+        let process = Process(
+            args: "xcrun", "simctl", "list", "--json", "devices"
+        )
+        try process.launch()
+        let result = try process.waitUntilExit()
+        guard result.exitStatus == .terminated(code: 0) else {
+            let errorOutput = try (result.utf8Output() + result.utf8stderrOutput()).spm_chuzzle() ?? ""
+            throw Error.listDevices(errorOutput: errorOutput)
+        }
+
+        switch result.output {
+        case .success(let bytes):
+            return Data(bytes)
+        case .failure(let error):
+            throw error
+        }
+    }
+}

Tests/xcode-simulator-toolTests/SimctlTests.swift

@@ -0,0 +1,16 @@
+import Foundation
+import XCTest
+@testable import XcodeSimulatorKit
+
+class SimctlTests: XCTestCase {
+    func testListDevices() throws {
+        let jsonData = try Simctl.listDevices()
+        let obj = try JSONSerialization.jsonObject(with: jsonData, options: [])
+        XCTAssertTrue(obj is [String: Any])
+        guard let dict = obj as? [String: Any] else {
+            return
+        }
+        XCTAssertEqual(dict.keys.count, 1)
+        XCTAssertEqual(dict.keys.first, "devices")
+    }
+}