Added IgnoreFile unit tests

Author: samdeane

Package.swift

@@ -114,7 +114,8 @@ var targets: [Target] = [
       "SwiftFormat",
       "_SwiftFormatTestSupport",
       .product(name: "Markdown", package: "swift-markdown"),
-    ] + swiftSyntaxDependencies(["SwiftOperators", "SwiftParser", "SwiftSyntax", "SwiftSyntaxBuilder"])
+    ] + swiftSyntaxDependencies(["SwiftOperators", "SwiftParser", "SwiftSyntax", "SwiftSyntaxBuilder"]),
+    resources: [.copy("Resources")]
   ),
 ]
 

Tests/SwiftFormatTests/Core/IgnoreFileTests.swift

@@ -0,0 +1,30 @@
+import SwiftFormat
+import XCTest
+
+final class IgnoreFileTests: XCTestCase {
+
+  func testMissingIgnoreFile() throws {
+    let url = Bundle.module.url(forResource: "missing", withExtension: "", subdirectory: "Ignore Files")
+    XCTAssertNotNil(url)
+    XCTAssertNil(try IgnoreFile(forDirectory: url!))
+  }
+
+  func testValidIgnoreFile() throws {
+    let url = Bundle.module.url(forResource: "valid", withExtension: "", subdirectory: "Ignore Files")
+    XCTAssertNotNil(url)
+    XCTAssertNotNil(try IgnoreFile(forDirectory: url!))
+  }
+
+  func testInvalidIgnoreFile() throws {
+    let url = Bundle.module.url(forResource: "invalid", withExtension: "", subdirectory: "Ignore Files")
+    XCTAssertNotNil(url)
+    XCTAssertThrowsError(try IgnoreFile(forDirectory: url!))
+  }
+
+  func testEmptyIgnoreFile() throws {
+    let url = Bundle.module.url(forResource: "empty", withExtension: "", subdirectory: "Ignore Files")
+    XCTAssertNotNil(url)
+    XCTAssertThrowsError(try IgnoreFile(forDirectory: url!))
+  }
+
+}

Tests/SwiftFormatTests/Resources/Ignore Files/empty/.swift-format-ignore

@@ -0,0 +1 @@
+this is an invalid pattern

Tests/SwiftFormatTests/Resources/Ignore Files/invalid/.swift-format-ignore

@@ -0,0 +1 @@
+*