added Go variant

- using homegrown approval test function

go/README.md

@@ -0,0 +1,22 @@
+## Theatrical-Players-Refactoring-Kata (Go)
+
+This variant provides the kata in [Go](www.golang.org).
+
+### Installation
+
+* Install Go 1.12 (or later)
+* In the directory of this file, run `go mod download`
+* You can then run tests with `go test ./...`
+
+### Approval Tests
+
+Approval tests are run with a basic home-grown approval function (see `approval_test.go`).
+
+In short, for a new test case of `TestPrinterPrintByApproval`:
+* Add a new `.in.json` file under `testdata/TestPrinterPrintByApproval`. You can copy an existing one for starters.
+* Run `go test ./...` - it should fail and complain about a missing file.
+* However, a `.out.txt` file will have been created - use this one as the new `.approved.txt` file.
+
+#### Approval-testing errors
+
+Right now, the error is tested in-line. You can convert this test to an approval-test as well.

go/go.mod

@@ -0,0 +1,5 @@
+module github.com/emilybache/Theatrical-Players-Refactoring-Kata/go
+
+go 1.13
+
+require github.com/leekchan/accounting v0.0.0-20190702062627-a09595581342

go/go.sum

@@ -0,0 +1,10 @@
+github.com/cockroachdb/apd v1.1.0 h1:3LFP3629v+1aKXU5Q37mxmRxX/pIu1nijXydLShEq5I=
+github.com/cockroachdb/apd v1.1.0/go.mod h1:8Sl8LxpKi29FqWXR16WEFZRNSz3SoPzUzeMeY4+DwBQ=
+github.com/leekchan/accounting v0.0.0-20190702062627-a09595581342 h1:vzuUv5azbeM31DiEL386i5eQESs5FNN2gDfkPowzNkk=
+github.com/leekchan/accounting v0.0.0-20190702062627-a09595581342/go.mod h1:VfQkU+lPM8fjkGqiTn6R+4MX4A/pVwE1XGdDBqp0JFk=
+github.com/lib/pq v1.0.0 h1:X5PMW56eZitiTeO7tKzZxFCSpbFZJtkMMooicw2us9A=
+github.com/lib/pq v1.0.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
+github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/shopspring/decimal v0.0.0-20180709203117-cd690d0c9e24 h1:pntxY8Ary0t43dCZ5dqY4YTJCObLY1kIXl0uzMv+7DE=
+github.com/shopspring/decimal v0.0.0-20180709203117-cd690d0c9e24/go.mod h1:M+9NzErvs504Cn4c5DxATwIqPbtswREoFCre64PpcG4=

go/theatre/StatementPrinter.go

@@ -0,0 +1,53 @@
+package theatre
+
+import (
+	"fmt"
+	"math"
+
+	"github.com/leekchan/accounting"
+)
+
+type StatementPrinter struct{}
+
+func (StatementPrinter) Print(invoice Invoice, plays map[string]Play) (string, error) {
+	totalAmount := 0
+	volumeCredits := 0
+	result := fmt.Sprintf("Statement for %s\n", invoice.Customer)
+
+	ac := accounting.Accounting{Symbol: "$", Precision: 2}
+
+	for _, perf := range invoice.Performances {
+		play := plays[perf.PlayID]
+		thisAmount := 0
+
+		switch play.Type {
+		case "tragedy":
+			thisAmount = 40000
+			if perf.Audience > 30 {
+				thisAmount += 1000 * (perf.Audience - 30)
+			}
+		case "comedy":
+			thisAmount = 30000
+			if perf.Audience > 20 {
+				thisAmount += 10000 + 500*(perf.Audience-20)
+			}
+			thisAmount += 300 * perf.Audience
+		default:
+			return "", fmt.Errorf("unknown type: %s", play.Type)
+		}
+
+		// add volume credits
+		volumeCredits += int(math.Max(float64(perf.Audience)-30, 0))
+		// add extra credit for every ten comedy attendees
+		if play.Type == "comedy" {
+			volumeCredits += int(math.Floor(float64(perf.Audience) / 5))
+		}
+
+		// print line for this order
+		result += fmt.Sprintf("  %s: %s (%d seats)\n", play.Name, ac.FormatMoney(float64(thisAmount)/100), perf.Audience)
+		totalAmount += thisAmount
+	}
+	result += fmt.Sprintf("Amount owed is %s\n", ac.FormatMoney(float64(totalAmount)/100))
+	result += fmt.Sprintf("You earned %d credits\n", volumeCredits)
+	return result, nil
+}

go/theatre/StatementPrinter_test.go

@@ -0,0 +1,74 @@
+package theatre_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/emilybache/Theatrical-Players-Refactoring-Kata/go/theatre"
+)
+
+func TestPrinterPrintByApproval(t *testing.T) {
+	verify(t, "json", "txt", func(t testing.TB, data []byte) []byte {
+		var in struct {
+			Plays []struct {
+				ID   string
+				Play struct {
+					Name string
+					Type string
+				}
+			}
+			Invoice struct {
+				Customer     string
+				Performances []struct {
+					PlayID   string
+					Audience int
+				}
+			}
+		}
+
+		if err := json.Unmarshal(data, &in); err != nil {
+			t.Fatalf("failed to unmarshal input data: %v", err)
+			return nil
+		}
+
+		// copy test-structure to production structure. Making use of matching types.
+		plays := make(map[string]theatre.Play)
+		invoice := theatre.Invoice{
+			Customer:     in.Invoice.Customer,
+			Performances: make([]theatre.Performance, 0, len(in.Invoice.Performances)),
+		}
+		for _, perf := range in.Invoice.Performances {
+			invoice.Performances = append(invoice.Performances, perf)
+		}
+		for _, identifiedPlay := range in.Plays {
+			plays[identifiedPlay.ID] = identifiedPlay.Play
+		}
+
+		var printer theatre.StatementPrinter
+		statement, err := printer.Print(invoice, plays)
+		if err != nil {
+			t.Fatalf("failed to create statement, unexpected error: %v", err)
+		}
+		return []byte(statement)
+	})
+}
+
+func TestStatementWithNewPlayTypes(t *testing.T) {
+	plays := map[string]theatre.Play{
+		"henry-v": {Name: "Henry V", Type: "history"},
+		"as-like": {Name: "As You Like It", Type: "pastoral"},
+	}
+	invoice := theatre.Invoice{
+		Customer: "BigCo",
+		Performances: []theatre.Performance{
+			{PlayID: "henry-v", Audience: 53},
+			{PlayID: "as-like", Audience: 55},
+		},
+	}
+
+	var printer theatre.StatementPrinter
+	_, err := printer.Print(invoice, plays)
+	if err == nil {
+		t.Errorf("Expected an error, got none")
+	}
+}

go/theatre/approval_test.go

@@ -0,0 +1,78 @@
+package theatre_test
+
+import (
+	"bytes"
+	"io/ioutil"
+	"path"
+	"strings"
+	"testing"
+)
+
+// verify runs a list of sub-tests using input data from the "testdata" subdirectory named after the current test.
+// All files with the suffix ".in.<inType>" are used as input for the test case function.
+// The name before the suffix is used as the base name for the files this function uses.
+//
+// What the function returns will be compared to the file with suffix ".approved.<outType>".
+// If its content does not match the result, or the file does not exist, the test fails and a file with suffix ".out.<outType>" is created.
+//
+// In case the function encounters an error, it can call Fatalf() on the passed test instance.
+// To verify errors as approved data, be sure to include the error in your structured data.
+//
+// This function reports problems of file access, as well as a failure if no input files were found.
+func verify(t *testing.T, inType string, outType string, testCase func(testing.TB, []byte) []byte) {
+	t.Helper()
+	datadir := path.Join("testdata", t.Name())
+	files, err := ioutil.ReadDir(datadir)
+	if err != nil {
+		t.Fatalf("could not read test directory: %v", err)
+	}
+	fullInSuffix := ".in." + inType
+	fullApprovedSuffix := ".approved." + outType
+	inputData := make(map[string][]byte)
+	approvedData := make(map[string][]byte)
+	for _, file := range files {
+		switch {
+		case file.IsDir():
+		case strings.HasSuffix(file.Name(), fullInSuffix):
+			data, err := ioutil.ReadFile(path.Join(datadir, file.Name()))
+			if err != nil {
+				t.Errorf("failed to read input file %s: %v", file.Name(), err)
+			}
+			inputData[file.Name()] = data
+		case strings.HasSuffix(file.Name(), fullApprovedSuffix):
+			data, err := ioutil.ReadFile(path.Join(datadir, file.Name()))
+			if err != nil {
+				t.Errorf("failed to read approved file %s: %v", file.Name(), err)
+			}
+			approvedData[file.Name()] = data
+		}
+	}
+	if len(inputData) == 0 {
+		t.Fatalf("no input files in %s - is this the intent?", datadir)
+	}
+	for rangedInFilename, rangedInData := range inputData {
+		inFilename := rangedInFilename
+		inData := rangedInData
+		t.Run(t.Name()+"/"+inFilename, func(t *testing.T) {
+			result := testCase(t, inData)
+
+			baseFilename := inFilename[:len(inFilename)-len(fullInSuffix)]
+			expected, hasApproved := approvedData[baseFilename+fullApprovedSuffix]
+			writeOutFile := false
+			switch {
+			case !hasApproved:
+				t.Errorf("no approved data available (file %s not available)", baseFilename+fullApprovedSuffix)
+				writeOutFile = true
+			case !bytes.Equal(expected, result):
+				t.Errorf("result does not match expectation")
+				writeOutFile = true
+			}
+			if writeOutFile {
+				err = ioutil.WriteFile(path.Join(datadir, baseFilename+".out."+outType), result, 0644)
+				if err != nil {
+					t.Errorf("failed to write output data: %v", err)
+				}
+			}
+		})
+	}
+}

go/theatre/testdata/.gitignore

@@ -0,0 +1 @@
+*.out.*

go/theatre/testdata/TestPrinterPrintByApproval/1.approved.txt

@@ -0,0 +1,6 @@
+Statement for BigCo
+  Hamlet: $650.00 (55 seats)
+  As You Like It: $580.00 (35 seats)
+  Othello: $500.00 (40 seats)
+Amount owed is $1,730.00
+You earned 47 credits

go/theatre/testdata/TestPrinterPrintByApproval/1.in.json

@@ -0,0 +1,15 @@
+{
+  "plays": [
+    { "id": "hamlet", "play": { "name": "Hamlet", "type": "tragedy" } },
+    { "id": "as-like", "play": { "name": "As You Like It", "type": "comedy" } },
+    { "id": "othello", "play": { "name": "Othello", "type": "tragedy" } }
+    ],
+  "invoice": {
+    "customer": "BigCo",
+    "performances": [
+      {"playId": "hamlet", "audience": 55 },
+      {"playId": "as-like", "audience": 35 },
+      {"playId": "othello", "audience": 40 }
+    ]
+  }
+}

go/theatre/types.go

@@ -0,0 +1,16 @@
+package theatre
+
+type Performance struct {
+	PlayID   string
+	Audience int
+}
+
+type Play struct {
+	Name string
+	Type string
+}
+
+type Invoice struct {
+	Customer     string
+	Performances []Performance
+}