SwiftLint/Source/SwiftLintFrameworkTests/LinterTests.swift

//
//  LinterTests.swift
//  SwiftLint
//
//  Created by JP Simard on 2015-05-16.
//  Copyright (c) 2015 Realm. All rights reserved.
//

import Foundation
import SwiftLintFramework
import SourceKittenFramework
import XCTest

func violations(string: String) -> [StyleViolation] {
    return Linter(file: File(contents: string)).styleViolations
}

class LinterTests: XCTestCase {

    // MARK: AST Violations

    func testTypeNames() {
        for kind in ["class", "struct", "enum"] {
            XCTAssertEqual(violations("\(kind) Abc {}\n"), [])

            XCTAssertEqual(violations("\(kind) Ab_ {}\n"), [StyleViolation(type: .NameFormat,
                location: Location(file: nil, line: 1),
                reason: "Type name should only contain alphanumeric characters: 'Ab_'")])

            XCTAssertEqual(violations("\(kind) abc {}\n"), [StyleViolation(type: .NameFormat,
                location: Location(file: nil, line: 1),
                reason: "Type name should start with an uppercase character: 'abc'")])

            XCTAssertEqual(violations("\(kind) Ab {}\n"), [StyleViolation(type: .NameFormat,
                location: Location(file: nil, line: 1),
                reason: "Type name should be between 3 and 40 characters in length: 'Ab'")])

            let longName = join("", Array(count: 40, repeatedValue: "A"))
            XCTAssertEqual(violations("\(kind) \(longName) {}\n"), [])
            let longerName = longName + "A"
            XCTAssertEqual(violations("\(kind) \(longerName) {}\n"), [
                StyleViolation(type: .NameFormat,
                    location: Location(file: nil, line: 1),
                    reason: "Type name should be between 3 and 40 characters in length: " +
                    "'\(longerName)'")
                ])
        }

        // Test typealias
        // TODO: Uncomment this once rdar://18845613 is fixed.
//        XCTAssertEqual(violations("typealias Abc = Void\n"), [])
//        XCTAssertEqual(violations("typealias abc = Void\n"), [StyleViolation(type: .NameFormat,
//            location: Location(file: nil),
//            reason: "Type name should start with an uppercase character: 'abc'")])

        // Test enum element
        // TODO: Uncomment this once rdar://18845613 is fixed.
//        XCTAssertEqual(violations("enum Abc { case Def }\n"), [])
//        XCTAssertEqual(violations("enum Abc { case def }\n"), [StyleViolation(type: .NameFormat,
//            location: Location(file: nil),
//            reason: "Type name should start with an uppercase character: 'def'")])

        // Test nested type
        XCTAssertEqual(violations("class Abc {\n    class Def {}\n}\n"), [])
        XCTAssertEqual(violations("class Abc {\n    class def\n}\n"),
            [
                StyleViolation(type: .NameFormat,
                    location: Location(file: nil, line: 2),
                    reason: "Type name should start with an uppercase character: 'def'")
            ])

        // TODO: Support generic type names.
    }

    func testVariableNames() {
        for kind in ["class", "struct"] {
            for varType in ["var", "let"] {
                XCTAssertEqual(violations("\(kind) Abc { \(varType) def: Void }\n"), [])

                XCTAssertEqual(violations("\(kind) Abc { \(varType) de_: Void }\n"), [
                    StyleViolation(type: .NameFormat,
                        location: Location(file: nil, line: 1),
                        reason: "Variable name should only contain alphanumeric characters: 'de_'")
                    ])

                XCTAssertEqual(violations("\(kind) Abc { \(varType) Def: Void }\n"), [
                    StyleViolation(type: .NameFormat,
                        location: Location(file: nil, line: 1),
                        reason: "Variable name should start with a lowercase character: 'Def'")
                    ])

                XCTAssertEqual(violations("\(kind) Abc { \(varType) de: Void }\n"), [
                    StyleViolation(type: .NameFormat,
                        location: Location(file: nil, line: 1),
                        reason: "Variable name should be between 3 and 40 characters in length: " +
                        "'de'")
                    ])

                let longName = join("", Array(count: 40, repeatedValue: "d"))
                XCTAssertEqual(violations("\(kind) Abc { \(varType) \(longName): Void }\n"), [])
                let longerName = longName + "d"
                XCTAssertEqual(violations("\(kind) Abc { \(varType) \(longerName): Void }\n"), [
                    StyleViolation(type: .NameFormat,
                        location: Location(file: nil, line: 1),
                        reason: "Variable name should be between 3 and 40 characters in length: " +
                        "'\(longerName)'")
                    ])
            }
        }
    }

    func testClosureLengths() {
        // TODO: Closures should be 20 lines or less.
    }

    func testFunctionBodyLengths() {
        let longFunctionBody = "func abc() {" +
            join("", Array(count: 40, repeatedValue: "\n")) +
            "}\n"
        XCTAssertEqual(violations(longFunctionBody), [])
        let longerFunctionBody = "func abc() {" +
            join("", Array(count: 41, repeatedValue: "\n")) +
            "}\n"
        XCTAssertEqual(violations(longerFunctionBody), [StyleViolation(type: .Length,
            location: Location(file: nil, line: 1),
            severity: .VeryLow,
            reason: "Function body should be span 40 lines or less: currently spans 41 lines")])
    }

    func testTypeBodyLengths() {
        for kind in ["class", "struct", "enum"] {
            let longTypeBody = "\(kind) Abc {" +
                join("", Array(count: 200, repeatedValue: "\n")) +
                "}\n"
            XCTAssertEqual(violations(longTypeBody), [])
            let longerTypeBody = "\(kind) Abc {" +
                join("", Array(count: 201, repeatedValue: "\n")) +
                "}\n"
            XCTAssertEqual(violations(longerTypeBody), [StyleViolation(type: .Length,
                location: Location(file: nil, line: 1),
                severity: .VeryLow,
                reason: "Type body should be span 200 lines or less: currently spans 201 lines")])
        }
    }

    func testNesting() {
        for kind in ["class", "struct", "enum"] {
            XCTAssertEqual(violations("\(kind) Class0 { \(kind) Class1 {} }\n"), [])
            XCTAssertEqual(violations("\(kind) Class0 { \(kind) Class1 { \(kind) Class2 {} } }\n"),
                [
                    StyleViolation(type: .Nesting,
                        location: Location(file: nil, line: 1),
                        reason: "Types should be nested at most 1 level deep")
                ])
        }
        XCTAssertEqual(violations(
            "func func0() {\nfunc func1() {\nfunc func2() {\nfunc func3() {\nfunc func4() { " +
            "func func5() {\n}\n}\n}\n}\n}\n}\n"
            ), [])
        XCTAssertEqual(violations(
            "func func0() {\nfunc func1() {\nfunc func2() {\nfunc func3() {\nfunc func4() { " +
            "func func5() {\nfunc func6() {\n}\n}\n}\n}\n}\n}\n}\n"
            ),
            [
                StyleViolation(type: .Nesting,
                    location: Location(file: nil, line: 6),
                    reason: "Statements should be nested at most 5 levels deep")
            ])
    }

    func testControlStatements() {
        // TODO: if,for,while,do statements shouldn't wrap their conditionals in parentheses.
    }

    func testNumberOfFunctionsInAType() {
        // TODO: Types should contain 10 functions or less.
    }

    func testTrailingClosureSyntax() {
        // TODO: Trailing closure syntax should be used whenever possible.
    }

    func testNoForceUnwrapping() {
        // TODO: Force unwrapping should not be used.
    }

    func testNoImplicitlyUnwrappedOptionals() {
        // TODO: Implicitly unwrapped optionals should not be used.
    }

    func testPreferImplicitGettersOnReadOnly() {
        // TODO: Read-only properties and subscripts should avoid using the `get` keyword.
    }

    func testExplicitAccessControlKeywordsForTopLevelDeclarations() {
        // TODO: Top-level declarations should use explicit ACL keywords
        //       (`public`, `internal`, `private`).
    }

    func testAvoidSelfOutsideClosuresAndConflicts() {
        // TODO: Use of `self` should be limited to closures and scopes in which other
        //       declarations conflict.
    }

    func testUseWhitespaceAroundOperatorDefinitions() {
        // TODO: Use whitespace around operator definitions.
        //
        // Good: `func <|< <A>(lhs: A, rhs: A) -> A`
        // Bad:  `func <|<<A>(lhs: A, rhs: A) -> A`
    }

    // MARK: String Violations

    func testLineLengths() {
        let longLine = join("", Array(count: 100, repeatedValue: "/")) + "\n"
        XCTAssertEqual(violations(longLine), [])
        let testCases: [(String, Int, ViolationSeverity)] = [
            ("/", 101, .VeryLow),
            (join("", Array(count: 21, repeatedValue: "/")), 121, .Low),
            (join("", Array(count: 51, repeatedValue: "/")), 151, .Medium),
            (join("", Array(count: 101, repeatedValue: "/")), 201, .High),
            (join("", Array(count: 151, repeatedValue: "/")), 251, .VeryHigh)
        ]
        for testCase in testCases {
            XCTAssertEqual(violations(testCase.0 + longLine), [StyleViolation(type: .Length,
                location: Location(file: nil, line: 1),
                severity: testCase.2,
                reason: "Line should be 100 characters or less: currently \(testCase.1) characters")])
        }
    }

    func testTrailingNewlineAtEndOfFile() {
        XCTAssertEqual(violations("//\n"), [])
        XCTAssertEqual(violations(""), [StyleViolation(type: .TrailingNewline,
            location: Location(file: nil),
            severity: .Medium,
            reason: "File should have a single trailing newline: currently has 0")])
        XCTAssertEqual(violations("//\n\n"), [StyleViolation(type: .TrailingNewline,
            location: Location(file: nil),
            severity: .Medium,
            reason: "File should have a single trailing newline: currently has 2")])
    }

    func testFileLengths() {
        XCTAssertEqual(violations(join("", Array(count: 400, repeatedValue: "//\n"))), [])
        let testCases: [(String, Int, ViolationSeverity)] = [
            (join("", Array(count: 401, repeatedValue: "//\n")), 401, .VeryLow),
            (join("", Array(count: 501, repeatedValue: "//\n")), 501, .Low),
            (join("", Array(count: 751, repeatedValue: "//\n")), 751, .Medium),
            (join("", Array(count: 1001, repeatedValue: "//\n")), 1001, .High),
            (join("", Array(count: 2001, repeatedValue: "//\n")), 2001, .VeryHigh)
        ]
        for testCase in testCases {
            XCTAssertEqual(violations(testCase.0), [StyleViolation(type: .Length,
                location: Location(file: nil),
                severity: testCase.2,
                reason: "File should contain 400 lines or less: currently contains \(testCase.1)")])
        }
    }

    func testFileShouldntStartWithWhitespace() {
        XCTAssertEqual(violations("//\n"), [])
        XCTAssertEqual(violations("\n"), [StyleViolation(type: .LeadingWhitespace,
            location: Location(file: nil, line: 1),
            severity: .Medium,
            reason: "File shouldn't start with whitespace: currently starts with 1 whitespace " +
            "characters")])
        XCTAssertEqual(violations(" //\n"), [StyleViolation(type: .LeadingWhitespace,
            location: Location(file: nil, line: 1),
            severity: .Medium,
            reason: "File shouldn't start with whitespace: currently starts with 1 whitespace " +
            "characters")])
    }

    func testLinesShouldntContainTrailingWhitespace() {
        XCTAssertEqual(violations("//\n"), [])
        XCTAssertEqual(violations("// \n"), [StyleViolation(type: .TrailingWhitespace,
            location: Location(file: nil, line: 1),
            severity: .Medium,
            reason: "Line #1 should have no trailing whitespace: current has 1 trailing " +
            "whitespace characters")])
    }

    func testForceCasting() {
        XCTAssertEqual(violations("NSNumber() as? Int\n"), [])
        XCTAssertEqual(violations("// NSNumber() as! Int\n"), [])
        XCTAssertEqual(violations("NSNumber() as! Int\n"),
            [StyleViolation(type: .ForceCast,
                location: Location(file: nil, line: 1),
                severity: .High,
                reason: "Force casts should be avoided")])
    }

    func testTodoOrFIXME() {
        for type in ["TODO", "FIXME"] {
            XCTAssertEqual(violations("let string = \"// \(type):\"\n"), [])
            XCTAssertEqual(violations("// \(type):\n"), [StyleViolation(type: .TODO,
                location: Location(file: nil, line: 1),
                reason: "TODOs and FIXMEs should be avoided")])
        }
    }

    func testColon() {
        let good = [
            "let abc: Void\n",
            "let abc: [Void: Void]\n",
            "let abc: (Void, Void)\n",
            "func abc(def: Void) {}\n"
        ]
        for string in good {
            XCTAssertEqual(violations(string), [])
        }

        let bad = [
            "let abc:Void\n",
            "let abc:  Void\n",
            "let abc :Void\n",
            "let abc : Void\n",
            "let abc : [Void: Void]\n",
            "func abc(def:Void) {}\n",
            "func abc(def:  Void) {}\n",
            "func abc(def :Void) {}\n",
            "func abc(def : Void) {}\n"
        ]
        for string in bad {
            XCTAssertEqual(violations(string).map({$0.type}), [.Colon])
        }

        for string in bad.map({ "// \($0)" }) {
            XCTAssertEqual(violations(string), [])
        }
    }
}