book-store: create test case generator

Add .meta/gen.go to generate cases_test.go.

Update test program to use generated test case array.

For exercism#605.

exercises/book-store/.meta/gen.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"log"
+	"text/template"
+
+	"../../../gen"
+)
+
+func main() {
+	t, err := template.New("").Parse(tmpl)
+	if err != nil {
+		log.Fatal(err)
+	}
+	var j js
+	if err := gen.Gen("book-store", &j, t); err != nil {
+		log.Fatal(err)
+	}
+}
+
+// The JSON structure we expect to be able to unmarshal into
+type js struct {
+	Cases  []OneCase
+	Groups []TestGroup `json:"cases"`
+}
+
+type TestGroup struct {
+	Description string
+	Cases       []OneCase
+}
+
+type OneCase struct {
+	Description string
+	Basket      []int
+	Expected    float64
+}
+
+// template applied to above data structure generates the Go test cases
+var tmpl = `package bookstore
+
+{{.Header}}
+
+var testCases = []struct {
+	description string
+	basket      []int
+	expected    float64
+}{{range .J.Groups}}{
+{{range .Cases}} {
+	description: "{{.Description}}",
+	basket:      {{printf "%#v" .Basket}},
+	expected:    {{printf "%.2f" .Expected}},
+},
+{{end}}}{{end}}
+`

exercises/book-store/book_store_test.go

@@ -4,73 +4,6 @@ import (
 	"testing"
 )
 
-var testCases = []struct {
-	description string
-	basket      []int
-	expected    float64
-}{
-	{
-		description: "only a single book",
-		basket:      []int{1},
-		expected:    8.00,
-	},
-	{
-		description: "two of the same book",
-		basket:      []int{2, 2},
-		expected:    16.00,
-	},
-	{
-		description: "empty basket",
-		basket:      []int{},
-		expected:    0.00,
-	},
-	{
-		description: "two different books",
-		basket:      []int{1, 2},
-		expected:    15.20,
-	},
-	{
-		description: "four different books",
-		basket:      []int{1, 2, 3, 4},
-		expected:    25.60,
-	},
-	{
-		description: "five different books",
-		basket:      []int{1, 2, 3, 4, 5},
-		expected:    30.00,
-	},
-	{
-		description: "two groups of four is cheaper than group of five plus group of three",
-		basket:      []int{1, 1, 2, 2, 3, 3, 4, 5},
-		expected:    51.20,
-	},
-	{
-		description: "groups of four plus group of two is is cheaper than two groups of three",
-		basket:      []int{1, 1, 2, 2, 3, 4},
-		expected:    40.80,
-	},
-	{
-		description: "two each of first 4 books and 1 copy of each of rest",
-		basket:      []int{1, 1, 2, 2, 3, 3, 4, 4, 5},
-		expected:    55.60,
-	},
-	{
-		description: "two copies of each book",
-		basket:      []int{1, 1, 2, 2, 3, 3, 4, 4, 5, 5},
-		expected:    60.00,
-	},
-	{
-		description: "three copies of first book and 2 each fo remaining",
-		basket:      []int{1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 1},
-		expected:    68.00,
-	},
-	{
-		description: "three each of first 2 books and 2 each of remaining books",
-		basket:      []int{1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 1, 2},
-		expected:    75.20,
-	},
-}
-
 func TestCost(t *testing.T) {
 	for _, testCase := range testCases {
 		cost := Cost(testCase.basket)

exercises/book-store/cases_test.go

@@ -0,0 +1,77 @@
+package bookstore
+
+// Source: exercism/problem-specifications
+// Commit: 087ad69 book-store: Add missing trailing zero
+// Problem Specifications Version: 1.0.1
+
+var testCases = []struct {
+	description string
+	basket      []int
+	expected    float64
+}{
+	{
+		description: "Only a single book",
+		basket:      []int{1},
+		expected:    8.00,
+	},
+	{
+		description: "Two of the same book",
+		basket:      []int{2, 2},
+		expected:    16.00,
+	},
+	{
+		description: "Empty basket",
+		basket:      []int{},
+		expected:    0.00,
+	},
+	{
+		description: "Two different books",
+		basket:      []int{1, 2},
+		expected:    15.20,
+	},
+	{
+		description: "Three different books",
+		basket:      []int{1, 2, 3},
+		expected:    21.60,
+	},
+	{
+		description: "Four different books",
+		basket:      []int{1, 2, 3, 4},
+		expected:    25.60,
+	},
+	{
+		description: "Five different books",
+		basket:      []int{1, 2, 3, 4, 5},
+		expected:    30.00,
+	},
+	{
+		description: "Two groups of four is cheaper than group of five plus group of three",
+		basket:      []int{1, 1, 2, 2, 3, 3, 4, 5},
+		expected:    51.20,
+	},
+	{
+		description: "Group of four plus group of two is cheaper than two groups of three",
+		basket:      []int{1, 1, 2, 2, 3, 4},
+		expected:    40.80,
+	},
+	{
+		description: "Two each of first 4 books and 1 copy each of rest",
+		basket:      []int{1, 1, 2, 2, 3, 3, 4, 4, 5},
+		expected:    55.60,
+	},
+	{
+		description: "Two copies of each book",
+		basket:      []int{1, 1, 2, 2, 3, 3, 4, 4, 5, 5},
+		expected:    60.00,
+	},
+	{
+		description: "Three copies of first book and 2 each of remaining",
+		basket:      []int{1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 1},
+		expected:    68.00,
+	},
+	{
+		description: "Three each of first 2 books and 2 each of remaining books",
+		basket:      []int{1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 1, 2},
+		expected:    75.20,
+	},
+}