👌 FileSystem changes, rework and testing

tests/unit/Testables/Shell/TestableShellTest.swift

@@ -0,0 +1,39 @@
+//
+//  TestableShellTest.swift
+//  PHP Monitor
+//
+//  Created by Nico Verbruggen on 20/09/2022.
+//  Copyright © 2022 Nico Verbruggen. All rights reserved.
+//
+
+import XCTest
+
+class TestableShellTest: XCTestCase {
+    func test_fake_shell_output_can_be_declared() async {
+        let greeting = BatchFakeShellOutput(items: [
+            .instant("Hello world\n"),
+            .delayed(0.3, "Goodbye world")
+        ])
+
+        let output = await greeting.outputInstantaneously()
+
+        XCTAssertEqual("Hello world\nGoodbye world", output.out)
+    }
+
+    func test_fake_shell_can_output_in_realtime() async {
+        let greeting = BatchFakeShellOutput(items: [
+            .instant("Hello world\n"),
+            .delayed(2, "Goodbye world")
+        ])
+
+        let output = await greeting.output(didReceiveOutput: { _, _ in })
+
+        XCTAssertEqual("Hello world\nGoodbye world", output.out)
+    }
+
+    func test_fake_shell_has_path() {
+        ActiveShell.useTestable([:])
+
+        XCTAssertEqual(Shell.PATH, "/usr/local/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin")
+    }
+}