SwiftUI unit tests examples for Lessons in SwiftUI blog post

swiftui-buttons-viewmodel-unit-tests.swift

class ButtonViewModelTests: XCTestCase {
    // ...

    func testDefaultConfig() {
        let vm = ButtonViewModel(iconMode: nil, inverse: false, size: .medium, type: .secondary)
        let size = ButtonSize.medium
        let type = ButtonType.secondary
        
        XCTAssertNil(vm.iconStyle)
        XCTAssertEqual(vm.selectedStyle, type.selectedStyle)
        XCTAssertEqual(vm.style, type.style)
        
        XCTAssertEqual(vm.cornerRadius, size.cornerRadius)
        XCTAssertEqual(vm.height, size.height)
        XCTAssertNil(vm.width)
        XCTAssertEqual(vm.horizontalPadding, size.horizontalPadding)
        
        XCTAssertEqual(vm.padding.top, 0)
        XCTAssertEqual(vm.padding.bottom, 0)
        XCTAssertEqual(vm.padding.leading, size.horizontalPadding)
        XCTAssertEqual(vm.padding.trailing, size.horizontalPadding)
        
        XCTAssertEqual(vm.typeStyle, size.typeStyle)
    }
    
    func testIconOnly() {
        let vm = ButtonViewModel(iconMode: .iconOnly, inverse: false, size: .medium, type: .secondary)
        let size = ButtonSize.medium
        let type = ButtonType.secondary
        
        XCTAssertEqual(vm.iconStyle, type.iconOnlyStyle)
        XCTAssertEqual(vm.width, size.height)
        XCTAssertEqual(vm.padding.top, 0)
        XCTAssertEqual(vm.padding.bottom, 0)
        XCTAssertEqual(vm.padding.leading, 0)
        XCTAssertEqual(vm.padding.trailing, 0)
        
        let inverseVM = ButtonViewModel(iconMode: .iconOnly, inverse: true, size: .medium, type: .secondary)
        XCTAssertEqual(inverseVM.iconStyle, type.iconOnlyInverseStyle)
    }
    
    func testIsPressedScaleEffect() {
        let vm = ButtonViewModel(iconMode: nil, inverse: false, size: .medium, type: .secondary)
        
        var isEnabled = true
        XCTAssertEqual(vm.scaleEffect(for: isEnabled, isPressed: true), 0.99)
        XCTAssertEqual(vm.scaleEffect(for: isEnabled, isPressed: false), 1.0)
        
        isEnabled = false
        XCTAssertEqual(vm.scaleEffect(for: isEnabled, isPressed: true), 1.0)
        XCTAssertEqual(vm.scaleEffect(for: isEnabled, isPressed: false), 1.0)
    }
    
    // ...
}