Add initial source code, with passing test

Tests/LinuxMain.swift

@@ -0,0 +1,7 @@
+import XCTest
+
+import drone_tutorial_swiftTests
+
+var tests = [XCTestCaseEntry]()
+tests += drone_tutorial_swiftTests.allTests()
+XCTMain(tests)

Tests/drone-tutorial-swiftTests/XCTestManifests.swift

@@ -0,0 +1,9 @@
+import XCTest
+
+#if !os(macOS)
+public func allTests() -> [XCTestCaseEntry] {
+    return [
+        testCase(drone_tutorial_swiftTests.allTests),
+    ]
+}
+#endif

Tests/drone-tutorial-swiftTests/drone_tutorial_swiftTests.swift

@@ -0,0 +1,15 @@
+import XCTest
+@testable import drone_tutorial_swift
+
+final class drone_tutorial_swiftTests: XCTestCase {
+    func testExample() {
+        // This is an example of a functional test case.
+        // Use XCTAssert and related functions to verify your tests produce the correct
+        // results.
+        XCTAssertEqual(drone_tutorial_swift().text, "Hello, World!")
+    }
+
+    static var allTests = [
+        ("testExample", testExample),
+    ]
+}