chore: Refactor Golang code

go/Makefile

@@ -0,0 +1,20 @@
+NAME := gilded-rose
+
+# set default compiler
+GO := go
+
+.PHONY: prebuild
+prebuild:
+
+all: lint test
+
+.PHONY: lint
+lint: ## Verifies `golint` passes.
+	@echo "+ $@"
+	@golint ./... | grep -v '.pb.go:' | grep -v vendor | tee /dev/stderr
+
+.PHONY: test
+test: prebuild ## Runs the go tests.
+	@echo "+ $@"
+	@$(GO) test -v $(shell $(GO) list ./... | grep -v vendor)
+

go/gilded-rose.go

@@ -1,58 +1,159 @@
 package main
 
+import "fmt"
+
 type Item struct {
 	name            string
 	sellIn, quality int
 }
 
-func UpdateQuality(items []*Item) {
-	for i := 0; i < len(items); i++ {
+var items = []Item{
+	Item{"+5 Dexterity Vest", 10, 20},
+	Item{"Aged Brie", 2, 0},
+	Item{"Elixir of the Mongoose", 5, 7},
+	Item{"Sulfuras, Hand of Ragnaros", 0, 80},
+	Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20},
+	Item{"Conjured Mana Cake", 3, 6},
+}
 
-		if items[i].name != "Aged Brie" && items[i].name != "Backstage passes to a TAFKAL80ETC concert" {
-			if items[i].quality > 0 {
-				if items[i].name != "Sulfuras, Hand of Ragnaros" {
-					items[i].quality = items[i].quality - 1
-				}
-			}
-		} else {
-			if items[i].quality < 50 {
-				items[i].quality = items[i].quality + 1
-				if items[i].name == "Backstage passes to a TAFKAL80ETC concert" {
-					if items[i].sellIn < 11 {
-						if items[i].quality < 50 {
-							items[i].quality = items[i].quality + 1
-						}
-					}
-					if items[i].sellIn < 6 {
-						if items[i].quality < 50 {
-							items[i].quality = items[i].quality + 1
-						}
-					}
-				}
-			}
-		}
+type Updatable interface {
+	Update()
+}
 
-		if items[i].name != "Sulfuras, Hand of Ragnaros" {
-			items[i].sellIn = items[i].sellIn - 1
-		}
+type UpdatableItem func(item *Item) Updatable
 
-		if items[i].sellIn < 0 {
-			if items[i].name != "Aged Brie" {
-				if items[i].name != "Backstage passes to a TAFKAL80ETC concert" {
-					if items[i].quality > 0 {
-						if items[i].name != "Sulfuras, Hand of Ragnaros" {
-							items[i].quality = items[i].quality - 1
-						}
-					}
-				} else {
-					items[i].quality = items[i].quality - items[i].quality
-				}
-			} else {
-				if items[i].quality < 50 {
-					items[i].quality = items[i].quality + 1
-				}
+type AgedBrieItem struct {
+	*Item
+}
+
+func (item *AgedBrieItem) Update() {
+	item.updateSellIn(-1)
+	if item.sellIn < 0 {
+		item.updateQuality(+2)
+	} else {
+		item.updateQuality(+1)
+	}
+	item.limitQualityToMax(50)
+}
+
+type SulfurasItem struct {
+	*Item
+}
+
+func (item *SulfurasItem) Update() {
+}
+
+type BackstagePassesItem struct {
+	*Item
+}
+
+func (item *BackstagePassesItem) Update() {
+	item.updateSellIn(-1)
+	sellIn := item.sellIn
+	switch {
+	case sellIn >= 10:
+		item.updateQuality(+1)
+	case sellIn < 10 && sellIn >= 5:
+		item.updateQuality(+2)
+	case sellIn < 15 && sellIn >= 0:
+		item.updateQuality(+3)
+	case sellIn < 0:
+		item.limitQualityToMax(0)
+	}
+	item.limitQualityToMax(50)
+}
+
+type RegularItem struct {
+	*Item
+}
+
+func (item *RegularItem) Update() {
+	item.updateSellIn(-1)
+	if item.sellIn < 0 {
+		item.updateQuality(-2)
+	} else {
+		item.updateQuality(-1)
+	}
+	item.limitQualityToMin(0)
+}
+
+type ConjuredItem struct {
+	*Item
+}
+
+func (item *ConjuredItem) Update() {
+	item.updateSellIn(-1)
+	if item.sellIn < 0 {
+		item.updateQuality(-4)
+	} else {
+		item.updateQuality(-2)
+	}
+	item.limitQualityToMin(0)
+}
+
+func UpdatableItemFactory(createClosure map[string]UpdatableItem, item *Item) Updatable {
+	create, exists := createClosure[item.name]
+	if exists {
+		return create(item)
+	}
+	return &RegularItem{
+		Item: item,
+	}
+}
+
+func (item *Item) updateSellIn(updatedBy int) {
+	item.sellIn += updatedBy
+}
+
+func (item *Item) updateQuality(updatedBy int) {
+	item.quality += updatedBy
+}
+
+func (item *Item) limitQualityToMax(max int) {
+	if item.quality > max {
+		item.quality = max
+	}
+}
+
+func (item *Item) limitQualityToMin(min int) {
+	if item.quality < min {
+		item.quality = min
+	}
+}
+
+func GildedRose(items []Item) {
+	creationMap := map[string]UpdatableItem{
+		"Aged Brie": func(item *Item) Updatable {
+			return &AgedBrieItem{
+				Item: item,
 			}
-		}
+		},
+		"Sulfuras, Hand of Ragnaros": func(item *Item) Updatable {
+			return &SulfurasItem{
+				Item: item,
+			}
+		},
+		"Backstage passes to a TAFKAL80ETC concert": func(item *Item) Updatable {
+			return &BackstagePassesItem{
+				Item: item,
+			}
+		},
+		"Conjured Mana Cake": func(item *Item) Updatable {
+			return &ConjuredItem{
+				Item: item,
+			}
+		},
 	}
 
+	for i := 0; i < len(items); i++ {
+		updatableItem := UpdatableItemFactory(creationMap, &items[i])
+		updatableItem.Update()
+	}
 }
+
+func main() {
+	fmt.Println("# Before updating")
+	// fmt.Println(items)
+	GildedRose(items)
+}
+

go/gilded-rose_test.go

@@ -1,15 +1,73 @@
 package main
 
-import "testing"
+import (
+	"fmt"
+	"io"
+	"os"
+	"testing"
+)
 
-func Test_Foo(t *testing.T) {
-	var items = []*Item{
-		&Item{"foo", 0, 0},
-	}
+var tests = []struct {
+	startItem    Item
+	expectedItem Item
+	days         int
+}{
+	{Item{"normal", 10, 20}, Item{"normal", 10, 20}, 0},
+	{Item{"normal", 10, 20}, Item{"normal", 0, 10}, 10},
+	{Item{"normal", 10, 20}, Item{"normal", -1, 8}, 11},
+	{Item{"normal", 10, 20}, Item{"normal", -20, 0}, 30},
+	{Item{"Aged Brie", 2, 0}, Item{"Aged Brie", 2, 0}, 0},
+	{Item{"Aged Brie", 2, 0}, Item{"Aged Brie", 0, 2}, 2},
+	{Item{"Aged Brie", 2, 0}, Item{"Aged Brie", -23, 48}, 25},
+	{Item{"Aged Brie", 2, 0}, Item{"Aged Brie", -24, 50}, 26},
+	{Item{"Aged Brie", 2, 0}, Item{"Aged Brie", -25, 50}, 27},
+	{Item{"Aged Brie", 2, 0}, Item{"Aged Brie", -28, 50}, 30},
+	{Item{"Sulfuras, Hand of Ragnaros", 0, 80}, Item{"Sulfuras, Hand of Ragnaros", 0, 80}, 0},
+	{Item{"Sulfuras, Hand of Ragnaros", 0, 80}, Item{"Sulfuras, Hand of Ragnaros", 0, 80}, 15},
+	{Item{"Sulfuras, Hand of Ragnaros", 0, 80}, Item{"Sulfuras, Hand of Ragnaros", 0, 80}, 30},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, 0},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 14, 21}, 1},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 13, 22}, 2},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 10, 25}, 5},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 9, 27}, 6},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 8, 29}, 7},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 5, 35}, 10},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 4, 38}, 11},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 3, 41}, 12},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", 0, 50}, 15},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", -1, 0}, 16},
+	{Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20}, Item{"Backstage passes to a TAFKAL80ETC concert", -10, 0}, 25},
+	{Item{"Conjured Mana Cake", 3, 6}, Item{"Conjured Mana Cake", 3, 6}, 0},
+	{Item{"Conjured Mana Cake", 3, 6}, Item{"Conjured Mana Cake", 2, 4}, 1},
+	{Item{"Conjured Mana Cake", 3, 6}, Item{"Conjured Mana Cake", 1, 2}, 2},
+	{Item{"Conjured Mana Cake", 3, 6}, Item{"Conjured Mana Cake", 0, 0}, 3},
+	{Item{"Conjured Mana Cake", 3, 6}, Item{"Conjured Mana Cake", -1, 0}, 4},
+	{Item{"Conjured Mana Cake", 3, 6}, Item{"Conjured Mana Cake", -2, 0}, 5},
+	{Item{"Conjured Mana Cake", 3, 6}, Item{"Conjured Mana Cake", -7, 0}, 10},
+}
 
-	UpdateQuality(items)
-
-	if items[0].name != "fixme" {
-		t.Errorf("Name: Expected %s but got %s ", "fixme", items[0].name)
+func TestGildedRose(t *testing.T) {
+	oldStdout := os.Stdout
+	r, w, _ := os.Pipe()
+	defer func() {
+		os.Stdout = oldStdout
+		w.Close()
+		if t.Failed() {
+			fmt.Println("=== Start Captured Stdout ===")
+			io.Copy(os.Stdout, r)
+			fmt.Println("=== End Captured Stdout ===")
+		}
+	}()
+	os.Stdout = w
+	for tn, test := range tests {
+		items = []Item{test.startItem}
+		for i := 0; i < test.days; i++ {
+			main()
+		}
+		if items[0] != test.expectedItem {
+			t.Logf("Test Number[%d]: Expected starting item %+v to equal %+v after %d days: Got %v", tn, test.startItem, test.expectedItem, test.days, items[0])
+			t.Fail()
+		}
 	}
 }
+

go/texttest_fixture.go

@@ -1,44 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"os"
-	"strconv"
-)
-
-func main() {
-	fmt.Println("OMGHAI!")
-
-	var items = []*Item{
-		&Item{"+5 Dexterity Vest", 10, 20},
-		&Item{"Aged Brie", 2, 0},
-		&Item{"Elixir of the Mongoose", 5, 7},
-		&Item{"Sulfuras, Hand of Ragnaros", 0, 80},
-		&Item{"Sulfuras, Hand of Ragnaros", -1, 80},
-		&Item{"Backstage passes to a TAFKAL80ETC concert", 15, 20},
-		&Item{"Backstage passes to a TAFKAL80ETC concert", 10, 49},
-		&Item{"Backstage passes to a TAFKAL80ETC concert", 5, 49},
-		&Item{"Conjured Mana Cake", 3, 6}, // <-- :O
-	}
-
-	days := 2
-	var err error
-	if len(os.Args) > 1 {
-		days, err = strconv.Atoi(os.Args[1])
-		if err != nil {
-			fmt.Println(err.Error())
-			os.Exit(1)
-		}
-		days++
-	}
-
-	for day := 0; day < days; day++ {
-		fmt.Printf("-------- day %d --------\n", day)
-		fmt.Println("name, sellIn, quality")
-		for i := 0; i < len(items); i++ {
-			fmt.Println(items[i])
-		}
-		fmt.Println("")
-		UpdateQuality(items)
-	}
-}