Add initial code

Tests/MakeColorsTests/ColorParserTest.swift

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+import XCTest
+@testable import LibMakeColors
+
+final class ColorParserTest: XCTestCase {
+    func testScanningThreeDigitColor() throws {
+        let scanner = Scanner(string: "#abc")
+        let color = scanner.color()
+        XCTAssertEqual(Color(r: 0xaa, g: 0xbb, b: 0xcc), color)
+    }
+
+    func testScanningFourDigitColor() throws {
+        let scanner = Scanner(string: "#abcd")
+        let color = scanner.color()
+        XCTAssertEqual(Color(r: 0xaa, g: 0xbb, b: 0xcc, a: 0xDD), color)
+    }
+
+
+    func testScanningSixDigitColor() throws {
+        let scanner = Scanner(string: "#abcdef")
+        let color = scanner.color()
+        XCTAssertEqual(Color(r: 0xab, g: 0xcd, b: 0xef), color)
+    }
+
+    func testScanningEightDigitColor() throws {
+        let scanner = Scanner(string: "#abcdef17")
+        let color = scanner.color()
+        XCTAssertEqual(Color(r: 0xab, g: 0xcd, b: 0xef, a: 0x17), color)
+    }
+
+    func testScanningRGBColor() throws {
+        let scanner = Scanner(string: "rgb(1,2,3)")
+        let color = scanner.color()
+        XCTAssertEqual(Color(r: 1, g: 2, b: 3), color)
+    }
+
+    func testScanningRGBAColor() throws {
+        let scanner = Scanner(string: "rgba(1,2,3,4)")
+        let color = scanner.color()
+        XCTAssertEqual(Color(r: 1, g: 2, b: 3, a: 4), color)
+    }
+
+}