         XCTAssertEqual(notes.count, 24)
     }
 
-    // Gb/G is boundary of transpostion.
-    func testTranspositionBoundary() {
+    func testTune_Equal_TranspositionBoundary() {
         let configuration = HarmonyKit.Configuration(
             temperament: .equal,
             pitch: 442,
+            // Gb/G is boundary of transpostion.
             transpositionTone: .G,
             octaveRange: 1..<2
         )

import HarmonyKit

final class HarmonyKitTests: XCTestCase {
    func testNotes_equalOneOctave() {
        let configuration = HarmonyKit.Configuration(
            temperament: .equal,
            pitch: 442,

        XCTAssertEqual(Set(notes), Set(expectedNotes))
    }

    func testTune_Pure_Major() {
        let configuration = HarmonyKit.Configuration(
            temperament: .pure(.major, rootTone: .C),
            pitch: 442,
            transpositionTone: .C,
            octaveRange: 1..<2
        )
        let notes = HarmonyKit.tune(configuration: configuration)
        XCTAssertEqual(notes.count, 12)

        let expectedNotes: [HarmonyKit.Note] = [
            .init(tone: .C, octave: 1, frequency: 32.851845),
            .init(tone: .Db, octave: 1, frequency: 34.221222),
            .init(tone: .D, octave: 1, frequency: 36.958115),
            .init(tone: .Eb, octave: 1, frequency: 39.421276),
            .init(tone: .E, octave: 1, frequency: 41.064487),
            .init(tone: .F, octave: 1, frequency: 43.801323),
            .init(tone: .Gb, octave: 1, frequency: 45.6271),
            .init(tone: .G, octave: 1, frequency: 49.279053),
            .init(tone: .Ab, octave: 1, frequency: 51.330196),
            .init(tone: .A, octave: 1, frequency: 54.754383),
            .init(tone: .Bb, octave: 1, frequency: 59.133453),
            .init(tone: .B, octave: 1, frequency: 61.598324)
        ]
        XCTAssertEqual(Set(notes), Set(expectedNotes))
    }

    func testTune_Pure_Minor() {
        let configuration = HarmonyKit.Configuration(
            temperament: .pure(.minor, rootTone: .C),
            pitch: 442,
            transpositionTone: .C,
            octaveRange: 1..<2
        )
        let notes = HarmonyKit.tune(configuration: configuration)
        XCTAssertEqual(notes.count, 12)

        let expectedNotes: [HarmonyKit.Note] = [
            .init(tone: .C, octave: 1, frequency: 32.851845),
            .init(tone: .Db, octave: 1, frequency: 35.479225),
            .init(tone: .D, octave: 1, frequency: 36.958115),
            .init(tone: .Eb, octave: 1, frequency: 39.421276),
            .init(tone: .E, octave: 1, frequency: 41.064487),
            .init(tone: .F, octave: 1, frequency: 43.801323),
            .init(tone: .Gb, octave: 1, frequency: 47.307137),
            .init(tone: .G, octave: 1, frequency: 49.279053),
            .init(tone: .Ab, octave: 1, frequency: 52.56337),
            .init(tone: .A, octave: 1, frequency: 54.754383),
            .init(tone: .Bb, octave: 1, frequency: 59.133453),
            .init(tone: .B, octave: 1, frequency: 61.598324),
        ]
        XCTAssertEqual(Set(notes), Set(expectedNotes))
    }

    func testTune_Pure_DifferentRoot() {
        let configuration = HarmonyKit.Configuration(
            temperament: .pure(.major, rootTone: .A),
            pitch: 442,
