From 8319b384bb08585f1a77367f189efd79abcd82c8 Mon Sep 17 00:00:00 2001 From: ferhat elmas Date: Tue, 18 Oct 2016 01:11:01 +0200 Subject: [PATCH] diamond: Add diamond exercise * property-based tests --- config.json | 5 + exercises/diamond/diamond_test.go | 227 ++++++++++++++++++++++++++++++ exercises/diamond/example.go | 47 +++++++ 3 files changed, 279 insertions(+) create mode 100644 exercises/diamond/diamond_test.go create mode 100644 exercises/diamond/example.go diff --git a/config.json b/config.json index fbdc1e50a..19e2572e3 100644 --- a/config.json +++ b/config.json @@ -211,6 +211,11 @@ "slug": "robot-name", "topics": [] }, + { + "difficulty": 1, + "slug": "diamond", + "topics": [] + }, { "difficulty": 1, "slug": "react", diff --git a/exercises/diamond/diamond_test.go b/exercises/diamond/diamond_test.go new file mode 100644 index 000000000..637287890 --- /dev/null +++ b/exercises/diamond/diamond_test.go @@ -0,0 +1,227 @@ +package diamond + +import ( + "math/rand" + "reflect" + "strings" + "testing" + "testing/quick" + "time" +) + +var config = &quick.Config{Rand: rand.New(rand.NewSource(time.Now().UnixNano()))} + +type correctChar byte + +func (c correctChar) Generate(rand *rand.Rand, _ int) reflect.Value { + return reflect.ValueOf(correctChar('A' + rand.Intn('Z'-'A'+1))) +} + +func checkCorrect(requirement func(byte, []string) bool, keepSeparator bool, t *testing.T) { + assertion := func(char correctChar) bool { + d, err := Gen(byte(char)) + if err != nil { + return false + } + separator := strings.Split + if keepSeparator { + separator = strings.SplitAfter + } + rows := separator(d, "\n") + if len(rows) < 2 { + return false + } + return requirement(byte(char), rows[:len(rows)-1]) + } + if err := quick.Check(assertion, config); err != nil { + t.Error(err) + } +} + +func TestFirstRowContainsOneA(t *testing.T) { + requirement := func(char byte, rows []string) bool { + return len(rows) > 0 && strings.Count(rows[0], "A") == 1 + } + checkCorrect(requirement, false, t) +} + +func TestLastRowContainsOneA(t *testing.T) { + requirement := func(char byte, rows []string) bool { + return len(rows) > 0 && strings.Count(rows[len(rows)-1], "A") == 1 + } + checkCorrect(requirement, false, t) +} + +func TestAllRowsIdenticalLettersExceptFirstAndLast(t *testing.T) { + requirement := func(char byte, rows []string) bool { + for i, row := range rows { + r := strings.TrimSpace(row) + if r[0] != r[len(r)-1] { + return false + } + if len(r) < 2 && i != 0 && i != len(rows)-1 { + return false + } + } + return true + } + checkCorrect(requirement, false, t) +} + +func TestAllRowsHaveSameTrailingSpaces(t *testing.T) { + requirement := func(char byte, rows []string) bool { + for _, row := range rows { + if len(row) == 0 { + return false + } + for i, j := 0, len(row)-1; i < j && row[i] == ' '; i, j = i+1, j-1 { + if row[j] != ' ' { + return false + } + } + } + return true + } + checkCorrect(requirement, false, t) +} + +func TestDiamondIsHorizontallySymmetric(t *testing.T) { + requirement := func(char byte, rows []string) bool { + for _, row := range rows { + l := len(row) + for i := l/2 - 1; i >= 0; i-- { + if row[i] != row[l-1-i] { + return false + } + } + } + return true + } + checkCorrect(requirement, false, t) +} + +func TestDiamondIsVerticallySymmetric(t *testing.T) { + requirement := func(char byte, rows []string) bool { + for i, j := 0, len(rows)-1; i < j; i, j = i+1, j-1 { + if rows[i] != rows[j] { + return false + } + } + return true + } + checkCorrect(requirement, true, t) +} + +func TestDiamondIsSquare(t *testing.T) { + requirement := func(char byte, rows []string) bool { + if int(char-'A')*2+1 != len(rows) { + return false + } + for _, row := range rows { + if len(row) != len(rows) { + return false + } + } + return true + } + checkCorrect(requirement, false, t) +} + +func TestDiamondHasItsShape(t *testing.T) { + requirement := func(char byte, rows []string) bool { + var n int + for i, row := range rows { + s := len(strings.TrimSpace(row)) + if i > len(rows)/2 && n <= s { + return false + } else if i <= len(rows)/2 && n >= s { + return false + } + n = s + } + return true + } + checkCorrect(requirement, false, t) +} + +func TestTopHalfHasAscendingLetters(t *testing.T) { + requirement := func(char byte, rows []string) bool { + var start byte = 'A' - 1 + for i := 0; i <= len(rows)/2; i++ { + s := strings.TrimLeft(rows[i], " ") + if s == "" || s[0] <= start { + return false + } + start = s[0] + } + return true + } + checkCorrect(requirement, false, t) +} + +func TestBottomHalfHasDescendingLetters(t *testing.T) { + requirement := func(char byte, rows []string) bool { + var start byte = 'A' - 1 + for i := len(rows) - 1; i > len(rows)/2; i-- { + s := strings.TrimLeft(rows[i], " ") + if s == "" || s[0] <= start { + return false + } + start = s[0] + } + return true + } + checkCorrect(requirement, false, t) +} + +func TestDiamondFourCornersAreTriangle(t *testing.T) { + requirement := func(char byte, rows []string) bool { + notSpace := func(r rune) bool { return r <= 'Z' && r >= 'A' } + var n int + for i, row := range rows { + s := strings.IndexFunc(row, notSpace) + e := len(row) - strings.LastIndexFunc(row, notSpace) - 1 + if s != e { + return false + } else if i == 0 { + n = s + } else { + if i > len(rows)/2 && n >= s { + return false + } else if i <= len(rows)/2 && n <= s { + return false + } + n = s + } + } + return true + } + checkCorrect(requirement, false, t) +} + +type wrongChar byte + +func (c wrongChar) Generate(rand *rand.Rand, _ int) reflect.Value { + b := rand.Intn(256) + for ; b >= 'A' && b <= 'Z'; b = rand.Intn(256) { + } + return reflect.ValueOf(wrongChar(b)) +} + +func TestCharOutOfRangeShouldGiveError(t *testing.T) { + assertion := func(char wrongChar) bool { + _, err := Gen(byte(char)) + return err != nil + } + if err := quick.Check(assertion, config); err != nil { + t.Error(err) + } +} + +const targetTestVersion = 1 + +func TestTestVersion(t *testing.T) { + if testVersion != targetTestVersion { + t.Errorf("Found testVersion = %v, want %v.", testVersion, targetTestVersion) + } +} diff --git a/exercises/diamond/example.go b/exercises/diamond/example.go new file mode 100644 index 000000000..47737a333 --- /dev/null +++ b/exercises/diamond/example.go @@ -0,0 +1,47 @@ +package diamond + +import ( + "errors" + "strings" +) + +const testVersion = 1 + +const startIndex = 'A' + +// Gen builds a diamond +func Gen(char byte) (string, error) { + if char > 'Z' || char < 'A' { + return "", errors.New(string(char) + " isn't supported, only between (A, Z)") + } + return gen(char), nil +} + +func gen(char byte) string { + var output []string + currentIndex := int(char - startIndex) + for i := 0; i <= currentIndex; i++ { + output = append(output, getLine(currentIndex, i)) + } + for i := currentIndex - 1; i > -1; i-- { + output = append(output, getLine(currentIndex, i)) + } + return strings.Join(output, "\n") + "\n" +} + +func getLine(currentStart, current int) string { + diff := currentStart - current + return spaces(diff) + alphabets(current) + spaces(diff) +} + +func alphabets(current int) string { + if current == 0 { + return "A" + } + c := current + startIndex + return string(c) + spaces(current*2-1) + string(c) +} + +func spaces(n int) string { + return strings.Repeat(" ", n) +}