Add commit checkers and their tests

DangerfileCoverage.swift

@@ -5,7 +5,7 @@ import Foundation
 let danger = Danger()
 
 if FileManager.default.fileExists(atPath: ".build/debug/codecov") {
-    Coverage.spmCoverage(minimumCoverage: 60)
+    Coverage.spmCoverage(minimumCoverage: 70)
 } else {
     warn("Cannot find SPM code coverage report, please run `swift test --enable-code-coverage` before danger.")
 }

Package.swift

@@ -22,10 +22,7 @@ let package = Package(
         .target(name: "DangerSwiftCommitLint", dependencies: [.product(name: "Danger", package: "danger-swift")]),
         .testTarget(
             name: "DangerSwiftCommitLintTests",
-            dependencies: [
-                "DangerSwiftCommitLint",
-                .product(name: "DangerFixtures", package: "danger-swift"),
-            ]
+            dependencies: ["DangerSwiftCommitLint"]
         ),
     ]
 )

Sources/DangerSwiftCommitLint/CommitChecker/BodyEmptyLineCheck.swift

@@ -0,0 +1,15 @@
+import Foundation
+
+struct BodyEmptyLineCheck: CommitChecker {
+    static var warningMessage = "Please separate commit message subject from body with newline."
+
+    private let bodyLinesOfText: [String]
+
+    init(message: CommitMessage) {
+        bodyLinesOfText = message.bodyLinesOfText
+    }
+
+    var fail: Bool {
+        bodyLinesOfText.isEmpty ? false : bodyLinesOfText.first?.isEmpty == false
+    }
+}

Sources/DangerSwiftCommitLint/CommitChecker/CommitChecker.swift

@@ -0,0 +1,16 @@
+import Foundation
+
+protocol CommitChecker: Hashable {
+    static var warningMessage: String { get }
+    var fail: Bool { get }
+
+    init(message: CommitMessage)
+
+    static func fail(message: CommitMessage) -> Bool
+}
+
+extension CommitChecker {
+    static func fail(message: CommitMessage) -> Bool {
+        Self(message: message).fail
+    }
+}

Sources/DangerSwiftCommitLint/CommitChecker/CommitMessage.swift

@@ -0,0 +1,28 @@
+import Danger
+import Foundation
+
+struct CommitMessage: Hashable {
+    /// First line of the commit message
+    let subject: String
+    /// Rest of the commit message
+    let bodyLinesOfText: [String]
+    // Commit SHA value
+    let sha: String
+
+    init(
+        subject: String,
+        bodyLinesOfText: [String],
+        sha: String
+    ) {
+        self.subject = subject
+        self.bodyLinesOfText = bodyLinesOfText
+        self.sha = sha
+    }
+
+    init(_ commit: GitHub.Commit) {
+        let commitMessageLines = commit.commit.message.components(separatedBy: .newlines)
+        subject = commitMessageLines.first ?? ""
+        bodyLinesOfText = Array(commitMessageLines.dropFirst())
+        sha = commit.sha
+    }
+}

Sources/DangerSwiftCommitLint/CommitChecker/SubjectCapCheck.swift

@@ -0,0 +1,15 @@
+import Foundation
+
+struct SubjectCapCheck: CommitChecker {
+    static let warningMessage = "Please start commit message subject with capital letter."
+
+    private let firstCharacter: Character?
+
+    init(message: CommitMessage) {
+        firstCharacter = message.subject.first
+    }
+
+    var fail: Bool {
+        firstCharacter?.isLowercase ?? false
+    }
+}

Sources/DangerSwiftCommitLint/CommitChecker/SubjectLengthCheck.swift

@@ -0,0 +1,26 @@
+import Foundation
+
+struct SubjectLengthCheck: CommitChecker {
+    private enum GeneratedSubjectPattern {
+        static let git = #"^Merge branch '.+' into "#
+        static let gitHub = #"^Merge pull request #\d+ from "#
+    }
+
+    static let warningMessage = "Please limit commit message subject line to 50 characters."
+
+    private let subject: String
+
+    init(message: CommitMessage) {
+        subject = message.subject
+    }
+
+    var fail: Bool {
+        subject.count > 50 && isMergeCommit == false
+    }
+}
+
+private extension SubjectLengthCheck {
+    var isMergeCommit: Bool {
+        subject =~ GeneratedSubjectPattern.git || subject =~ GeneratedSubjectPattern.gitHub
+    }
+}

Sources/DangerSwiftCommitLint/CommitChecker/SubjectPeriodCheck.swift

@@ -0,0 +1,15 @@
+import Foundation
+
+struct SubjectPeriodCheck: CommitChecker {
+    static var warningMessage = "Please remove period from end of commit message subject line."
+
+    private let subject: String
+
+    init(message: CommitMessage) {
+        subject = message.subject
+    }
+
+    var fail: Bool {
+        subject.last == "."
+    }
+}

Sources/DangerSwiftCommitLint/CommitChecker/SubjectWordCheck.swift

@@ -0,0 +1,15 @@
+import Foundation
+
+struct SubjectWordCheck: CommitChecker {
+    static var warningMessage = "Please use more than one word in commit message."
+
+    private let subject: String
+
+    init(message: CommitMessage) {
+        subject = message.subject
+    }
+
+    var fail: Bool {
+        subject.split(separator: " ").count < 2
+    }
+}

Sources/DangerSwiftCommitLint/DangerSwiftCommitLint.swift

@@ -1,4 +1,4 @@
 import Danger
 import Foundation
 
-final class DangerSwiftCommitLint {}
+public final class DangerSwiftCommitLint {}

Sources/DangerSwiftCommitLint/Extensions/RegexHelper.swift

@@ -0,0 +1,33 @@
+import Foundation
+
+infix operator =~: RegularExpressionPrecedence
+precedencegroup RegularExpressionPrecedence {
+    associativity: none
+    higherThan: AdditionPrecedence
+    lowerThan: MultiplicationPrecedence
+}
+
+func =~ (input: String, regexPattern: String) -> Bool {
+    do {
+        return try RegexHelper(regexPattern).match(input)
+    } catch {
+        return false
+    }
+}
+
+private struct RegexHelper {
+    private let regex: NSRegularExpression
+
+    init(_ pattern: String) throws {
+        regex = try NSRegularExpression(pattern: pattern, options: [])
+    }
+
+    func match(_ input: String) -> Bool {
+        regex.matches(
+            in: input,
+            options: [],
+            range: NSRange(location: 0, length: input.utf16.count)
+        )
+        .count > 0
+    }
+}

Tests/DangerSwiftCommitLintTests/CommitChecker/BodyEmptyLineCheckTests.swift

@@ -0,0 +1,27 @@
+import Danger
+@testable import DangerSwiftCommitLint
+import XCTest
+
+final class BodyEmptyLineCheckTests: XCTestCase {
+    private let commitSubjectAndBody = CommitMessage(subject: "Title Test", bodyLinesOfText: ["", "Body Test"], sha: "Test SHA")
+    private let commitSubjectOnly = CommitMessage(subject: "Title Test", bodyLinesOfText: [], sha: "Test SHA")
+    private let commitNoNewline = CommitMessage(subject: "Title Test", bodyLinesOfText: ["Body Test"], sha: "Test SHA")
+
+    func testSuccessCommitSubjectAndBody() {
+        let testSubject = BodyEmptyLineCheck(message: commitSubjectAndBody)
+        XCTAssertFalse(testSubject.fail)
+        XCTAssertFalse(BodyEmptyLineCheck.fail(message: commitSubjectAndBody))
+    }
+
+    func testSuccessSubjectOnly() {
+        let testSubject = BodyEmptyLineCheck(message: commitSubjectOnly)
+        XCTAssertFalse(testSubject.fail)
+        XCTAssertFalse(BodyEmptyLineCheck.fail(message: commitSubjectOnly))
+    }
+
+    func testFailureNoNewlineOnly() {
+        let testSubject = BodyEmptyLineCheck(message: commitNoNewline)
+        XCTAssertTrue(testSubject.fail)
+        XCTAssertTrue(BodyEmptyLineCheck.fail(message: commitNoNewline))
+    }
+}

Tests/DangerSwiftCommitLintTests/CommitChecker/CommitMessageTests.swift

@@ -0,0 +1,20 @@
+import Danger
+@testable import DangerSwiftCommitLint
+import XCTest
+
+final class CommitMessageTests: XCTestCase {
+    func testInitializeWithDangerGitHubCommit() {
+        let commit = CommitParser.parseCommitJSON(with: commitMessageJSON)
+        let expectedCommitMessage = commit.commit.message.components(separatedBy: .newlines)
+        let testSubject = CommitMessage(commit)
+        XCTAssertEqual(testSubject.sha, commit.sha)
+        XCTAssertEqual(
+            [
+                [testSubject.subject],
+                testSubject.bodyLinesOfText,
+            ]
+            .flatMap { $0 },
+            expectedCommitMessage
+        )
+    }
+}

Tests/DangerSwiftCommitLintTests/CommitChecker/Fixtures/CommitJSONParser.swift

@@ -0,0 +1,11 @@
+import Danger
+import Foundation
+
+enum CommitParser {
+    static func parseCommitJSON(with commitJSON: String) -> GitHub.Commit {
+        let data = Data(commitJSON.utf8)
+        let decoder = JSONDecoder()
+        decoder.dateDecodingStrategy = .custom(DateFormatter.dateFormatterHandler)
+        return try! decoder.decode(GitHub.Commit.self, from: data) // swiftlint:disable:this force_try
+    }
+}

Tests/DangerSwiftCommitLintTests/CommitChecker/Fixtures/CommitMessageJSON.swift

@@ -0,0 +1,78 @@
+let commitMessageJSON = """
+{
+    "sha": "93ae30cf2aee4241c442fb3242543490998cffdb",
+    "commit": {
+        "author": {
+            "name": "Ash Furrow",
+            "email": "[email protected]",
+            "date": "2016-07-26T19:54:16Z"
+        },
+        "committer": {
+            "name": "Ash Furrow",
+            "email": "[email protected]",
+            "date": "2016-07-26T19:55:00Z"
+        },
+        "message": "[Xcode] Updates for compatibility with Xcode 7.3.1.\\n\\nTest only",
+        "tree": {
+            "sha": "fb6bc3fda2456c5ff0a4e8f307f24ee73f281fc1",
+            "url": "https://api.github.com/repos/artsy/eidolon/git/trees/fb6bc3fda2456c5ff0a4e8f307f24ee73f281fc1"
+        },
+        "url": "https://api.github.com/repos/artsy/eidolon/git/commits/93ae30cf2aee4241c442fb3242543490998cffdb",
+        "comment_count": 0,
+        "verification": {
+            "verified": true,
+            "reason": "valid",
+            "signature": "-----BEGIN PGP SIGNATURE-----\\nVersion: GnuPG   v1\\n\\niQEcBAABAgAGBQJXl8AUAAoJEAGZOscENF/tIA8H/Ri9VdHJAzfO1aAtnoQ5W8Kw\\n1yYd5BTVnr0nVw95qxBgoRbBLMUIKg0TOPQQa1h7hk6SO0py6  E4HSpCJQq97f8J\\nvgeiFHuyfcW/ePSS8WwJbIzTP3xkckvdZIPjXM1KtvzQ1vCoOrOwBxMqH2twoTQk\\nuGd5cgfsahUGHcwYA6B4vfkmAGLkOyFVjUzbgf1n  T5CMbPVlbFgss3aEi8Ql81S\\ncNjtMGiUm9n3LUG5lMiwOC3898fpE8YYoAPy1CtLuwokGws3Tu9jMSnUCi2Al7KC\\nzWMpIS3L2WVoCdhiv2NbXxUDTban8ll   KGdtzw3QLZ0AL5ZEkuKrxtDQGyimpaw=\\n=aGrl\\n-----END PGP SIGNATURE-----",
+            "payload": "tree fb6bc3fda2456c5ff0a4e8f307f24ee73f281fc1\\nparent 68c8db83776c1942145f530159a3fffddb812577\\nauthor AshFurrow     <[email protected]> 1469562856 -0400\\ncommitter Ash Furrow <[email protected]> 1469562900 -0400\\n\\n[Xcode]Updates for   compatibility with Xcode 7.3.1.\\n"
+        }
+    },
+    "url": "https://api.github.com/repos/artsy/eidolon/commits/93ae30cf2aee4241c442fb3242543490998cffdb",
+    "html_url": "https://github.com/artsy/eidolon/commit/93ae30cf2aee4241c442fb3242543490998cffdb",
+    "comments_url": "https://api.github.com/repos/artsy/eidolon/commits/93ae30cf2aee4241c442fb3242543490998cffdb/comments",
+    "author": {
+        "login": "ashfurrow",
+        "id": 498212,
+        "avatar_url": "https://avatars3.githubusercontent.com/u/498212?v=4",
+        "gravatar_id": "",
+        "url": "https://api.github.com/users/ashfurrow",
+        "html_url": "https://github.com/ashfurrow",
+        "followers_url": "https://api.github.com/users/ashfurrow/followers",
+        "following_url": "https://api.github.com/users/ashfurrow/following{/other_user}",
+        "gists_url": "https://api.github.com/users/ashfurrow/gists{/gist_id}",
+        "starred_url": "https://api.github.com/users/ashfurrow/starred{/owner}{/repo}",
+        "subscriptions_url": "https://api.github.com/users/ashfurrow/subscriptions",
+        "organizations_url": "https://api.github.com/users/ashfurrow/orgs",
+        "repos_url": "https://api.github.com/users/ashfurrow/repos",
+        "events_url": "https://api.github.com/users/ashfurrow/events{/privacy}",
+        "received_events_url": "https://api.github.com/users/ashfurrow/received_events",
+        "type": "User",
+        "site_admin": false
+    },
+    "committer": {
+        "login": "ashfurrow",
+        "id": 498212,
+        "avatar_url": "https://avatars3.githubusercontent.com/u/498212?v=4",
+        "gravatar_id": "",
+        "url": "https://api.github.com/users/ashfurrow",
+        "html_url": "https://github.com/ashfurrow",
+        "followers_url": "https://api.github.com/users/ashfurrow/followers",
+        "following_url": "https://api.github.com/users/ashfurrow/following{/other_user}",
+        "gists_url": "https://api.github.com/users/ashfurrow/gists{/gist_id}",
+        "starred_url": "https://api.github.com/users/ashfurrow/starred{/owner}{/repo}",
+        "subscriptions_url": "https://api.github.com/users/ashfurrow/subscriptions",
+        "organizations_url": "https://api.github.com/users/ashfurrow/orgs",
+        "repos_url": "https://api.github.com/users/ashfurrow/repos",
+        "events_url": "https://api.github.com/users/ashfurrow/events{/privacy}",
+        "received_events_url": "https://api.github.com/users/ashfurrow/received_events",
+        "type": "User",
+        "site_admin": false
+    },
+    "parents": [
+        {
+            "sha": "68c8db83776c1942145f530159a3fffddb812577",
+            "url": "https://api.github.com/repos/artsy/eidolon/commits/68c8db83776c1942145f530159a3fffddb812577",
+            "html_url": "https://github.com/artsy/eidolon/commit/68c8db83776c1942145f530159a3fffddb812577"
+        }
+    ]
+}
+"""

Tests/DangerSwiftCommitLintTests/CommitChecker/SubjectCapCheckTests.swift

@@ -0,0 +1,33 @@
+@testable import DangerSwiftCommitLint
+import XCTest
+
+final class SubjectCapCheckTests: XCTestCase {
+    func testSuccess() {
+        let commitMessage = CommitMessage(subject: "Subject", bodyLinesOfText: [], sha: "Test SHA")
+        let testSubject = SubjectCapCheck(message: commitMessage)
+        XCTAssertFalse(testSubject.fail)
+        XCTAssertFalse(SubjectCapCheck.fail(message: commitMessage))
+    }
+
+    func testFailure() {
+        let commitMessage = CommitMessage(subject: "subject", bodyLinesOfText: [], sha: "Test SHA")
+        let testSubject = SubjectCapCheck(message: commitMessage)
+        XCTAssertTrue(testSubject.fail)
+        XCTAssertTrue(SubjectCapCheck.fail(message: commitMessage))
+    }
+
+    func testSuccessWithNonLetterCharacters() {
+        let commitMessage = CommitMessage(subject: "[TEST-123] Subject", bodyLinesOfText: [], sha: "Test SHA")
+        let testSubject = SubjectCapCheck(message: commitMessage)
+        XCTAssertFalse(testSubject.fail)
+        XCTAssertFalse(SubjectCapCheck.fail(message: commitMessage))
+    }
+
+    /// Git generally disallows empty commit message, so subject should at least contain non empty text. This test case is only capturing a unlikely edge case.
+    func testEdgeCase() {
+        let commitMessage = CommitMessage(subject: "", bodyLinesOfText: [], sha: "Test SHA")
+        let testSubject = SubjectCapCheck(message: commitMessage)
+        XCTAssertFalse(testSubject.fail)
+        XCTAssertFalse(SubjectCapCheck.fail(message: commitMessage))
+    }
+}