Add Gzip tests

Tests/GzipTests/GzipTests.swift

@@ -0,0 +1,135 @@
+//
+//  GzipTests.swift
+//  GzipTests
+//
+//  Created by 1024jp on 2015-05-11.
+
+/*
+ The MIT License (MIT)
+
+ © 2015-2019 1024jp
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ THE SOFTWARE.
+ */
+
+import XCTest
+import Binary
+import Gzip
+
+final class GzipTests: XCTestCase {
+
+    func testGZip() throws {
+
+        for _ in 0..<10 {
+            let testSentence = String.lorem(length: Int.random(in: 1..<100_000))
+
+            let bytes = testSentence.bytes(using: .utf8)!
+            let gzipped = try bytes.gzipped()
+            let uncompressed = try gzipped.gunzipped()
+            let uncompressedSentence = String(bytes: uncompressed, encoding: .utf8)
+
+            XCTAssertNotEqual(gzipped, bytes)
+            XCTAssertEqual(uncompressedSentence, testSentence)
+
+            XCTAssertTrue(gzipped.isGzipped)
+            XCTAssertFalse(bytes.isGzipped)
+            XCTAssertFalse(uncompressed.isGzipped)
+        }
+    }
+
+
+    func testZeroLength() throws {
+
+        let zeroLengthBytes = Bytes()
+
+        XCTAssertEqual(try zeroLengthBytes.gzipped(), zeroLengthBytes)
+        XCTAssertEqual(try zeroLengthBytes.gunzipped(), zeroLengthBytes)
+        XCTAssertFalse(zeroLengthBytes.isGzipped)
+    }
+
+
+    func testWrongUngzip() {
+
+        // data not compressed
+        let bytes = "testString".bytes(using: .utf8)!
+
+        var uncompressed: Bytes?
+        do {
+            uncompressed = try bytes.gunzipped()
+
+        } catch let error as GzipError where error.kind == .data {
+            XCTAssertEqual(error.message, "incorrect header check")
+            XCTAssertEqual(error.message, error.localizedDescription)
+
+        } catch _ {
+            XCTFail("Caught incorrect error.")
+        }
+
+        XCTAssertNil(uncompressed)
+    }
+
+
+    func testCompressionLevel() throws {
+
+        let bytes = String.lorem(length: 100_000).bytes(using: .utf8)!
+
+        XCTAssertGreaterThan(try bytes.gzipped(level: .bestSpeed).count,
+                             try bytes.gzipped(level: .bestCompression).count)
+    }
+
+
+    func testFileDecompression() throws {
+
+        let url = self.bundleFile(name: "test.txt.gz")
+        let bytes = try Bytes(contentsOf: url)
+        let uncompressed = try bytes.gunzipped()
+
+        XCTAssertTrue(bytes.isGzipped)
+        XCTAssertEqual(String(bytes: uncompressed, encoding: .utf8), "test")
+    }
+
+}
+
+private extension XCTestCase {
+
+    /// Create URL for bundled test file considering platform.
+    ///
+    /// - Parameter name: The file name to load in resources.
+    func bundleFile(name: String) -> URL {
+        guard let url = Bundle.module.url(forResource: name, withExtension: nil) else {
+            fatalError("can't find resource named: '\(name)'")
+        }
+
+        return url
+    }
+}
+
+private extension String {
+
+    /// Generate random letters string for test.
+    static func lorem(length: Int) -> String {
+
+        let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 "
+
+        return (0..<length).reduce(into: "") { (string, _) in
+            string.append(letters.randomElement()!)
+        }
+    }
+
+}