SwiftFormat/Sources/Rules/NoForceTryInTests.swift

// Created by Andy Bartholomew on 5/30/25.
// Copyright © 2025 Airbnb Inc. All rights reserved.

import Foundation

public extension FormatRule {
    static let noForceTryInTests = FormatRule(
        help: "Write tests that use `throws` instead of using `try!`."
    ) { formatter in
        guard let testFramework = formatter.detectTestingFramework() else {
            return
        }

        formatter.forEach(.keyword("func")) { funcKeywordIndex, _ in
            guard let functionDecl = formatter.parseFunctionDeclaration(keywordIndex: funcKeywordIndex),
                  formatter.isTestCase(at: funcKeywordIndex, in: functionDecl, for: testFramework),
                  let bodyRange = functionDecl.bodyRange
            else { return }

            // Find all `try!` and remove the `!`
            var foundAnyTryExclamationMarks = false
            for index in bodyRange.reversed() {
                guard formatter.tokens[index] == .keyword("try") else { continue }
                guard let nextTokenIndex = formatter.index(of: .nonSpaceOrCommentOrLinebreak, after: index)
                else { return }
                let nextToken = formatter.tokens[nextTokenIndex]
                if nextToken != .operator("!", .postfix) { continue }

                // Only remove the `!` if we are not within a closure or nested function,
                // where it's not safe to just remove the `!` and make our function throw.
                guard formatter.tryKeywordSupported(at: index, in: functionDecl) else { continue }

                formatter.removeToken(at: nextTokenIndex)
                foundAnyTryExclamationMarks = true
            }

            // If we found any `!`s, add a `throws` if it doesn't already exist.
            guard foundAnyTryExclamationMarks else { return }

            formatter.addThrowsEffect(to: functionDecl)
        }
    } examples: {
        """
        ```diff
            import Testing

            struct MyFeatureTests {
        -       @Test func doSomething() {
        +       @Test func doSomething() throws {
        -           try! MyFeature().doSomething()
        +           try MyFeature().doSomething()
              }
            }

            import XCTeset

            class MyFeatureTests: XCTestCase {
        -       func test_doSomething() {
        +       func test_doSomething() throws {
        -           try! MyFeature().doSomething()
        +           try MyFeature().doSomething()
              }
            }
        ```
        """
    }
}