clockface: xml

clockface/clockface.go

@@ -1,6 +1,8 @@
 package clockface
 
 import (
+	"fmt"
+	"io"
 	"math"
 	"time"
 )
@@ -11,13 +13,43 @@ type Point struct {
 	Y float64
 }
 
+const (
+	secondHandLength = 90
+	clockCentreX     = 150
+	clockCentreY     = 150
+)
+
+const svgStart = `<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg xmlns="http://www.w3.org/2000/svg"
+     width="100%"
+     height="100%"
+     viewBox="0 0 300 300"
+     version="2.0">`
+
+const bezel = `<circle cx="150" cy="150" r="100" style="fill:#fff;stroke:#000;stroke-width:5px;"/>`
+
+const svgEnd = `</svg>`
+
+func SVGWriter(w io.Writer, t time.Time) {
+	io.WriteString(w, svgStart)
+	io.WriteString(w, bezel)
+	SecondHand(w, t)
+	io.WriteString(w, svgEnd)
+}
+
 // SecondHand is the unit vector of the second hand of an analogue clock at the time `t` represented as a Point
-func SecondHand(t time.Time) Point {
+func SecondHand(w io.Writer, t time.Time) {
 	p := secondHandPoint(t)
-	p = Point{p.X * 90, p.Y * 90}   // scale
+	p = Point{p.X * secondHandLength, p.Y * secondHandLength} // scale
 	p = Point{p.X, -p.Y}                                      // flip
-	p = Point{p.X + 150, p.Y + 150} // translate
+	p = Point{p.X + clockCentreX, p.Y + clockCentreY}         // translate
-	return p
+	fmt.Fprintf(
+		w,
+		`<line x1="150" y1="150" x2="%f" y2="%f" style="fill:none;stroke:#f00;stroke-width:3px;"/>`,
+		p.X,
+		p.Y,
+	)
 }
 
 func secondsInRadians(t time.Time) float64 {

clockface/clockface_acceptance_test.go

@@ -1,28 +1,81 @@
 package clockface
 
 import (
+	"bytes"
+	"encoding/xml"
 	"testing"
 	"time"
 )
 
-func TestSecondHandAtMidnight(t *testing.T) {
+type Svg struct {
+	XMLName xml.Name `xml:"svg"`
+	Text    string   `xml:",chardata"`
+	Xmlns   string   `xml:"xmlns,attr"`
+	Width   string   `xml:"width,attr"`
+	Height  string   `xml:"height,attr"`
+	ViewBox string   `xml:"viewBox,attr"`
+	Version string   `xml:"version,attr"`
+	Circle  struct {
+		Text  string `xml:",chardata"`
+		Cx    string `xml:"cx,attr"`
+		Cy    string `xml:"cy,attr"`
+		R     string `xml:"r,attr"`
+		Style string `xml:"style,attr"`
+	} `xml:"circle"`
+	Line []struct {
+		Text  string `xml:",chardata"`
+		X1    string `xml:"x1,attr"`
+		Y1    string `xml:"y1,attr"`
+		X2    string `xml:"x2,attr"`
+		Y2    string `xml:"y2,attr"`
+		Style string `xml:"style,attr"`
+	} `xml:"line"`
+}
+
+// func TestSecondHandAtMidnight(t *testing.T) {
+// 	tm := time.Date(1337, time.January, 1, 0, 0, 0, 0, time.UTC)
+//
+// 	want := Point{X: 150, Y: 150 - 90}
+// 	got := SecondHand(tm)
+//
+// 	if got != want {
+// 		t.Errorf("Got %v, wanted %v", got, want)
+// 	}
+// }
+
+// func TestSecondHandAt30Seconds(t *testing.T) {
+// 	tm := time.Date(1337, time.January, 1, 0, 0, 30, 0, time.UTC)
+//
+// 	want := Point{X: 150, Y: 150 + 90}
+// 	got := SecondHand(tm)
+//
+// 	if got != want {
+// 		t.Errorf("Got %v, wanted %v", got, want)
+// 	}
+// }
+
+func TestSVGWriterAtMidnight(t *testing.T) {
 	tm := time.Date(1337, time.January, 1, 0, 0, 0, 0, time.UTC)
 
-	want := Point{X: 150, Y: 150 - 90}
+	b := bytes.Buffer{}
-	got := SecondHand(tm)
+	SVGWriter(&b, tm)
 
-	if got != want {
+	svg := Svg{}
-		t.Errorf("Got %v, wanted %v", got, want)
+	xml.Unmarshal(b.Bytes(), &svg)
+
+	x2 := "150.000000"
+	y2 := "60.000000"
+
+	for _, line := range svg.Line {
+		if line.X2 == x2 && line.Y2 == y2 {
+			return
 		}
 	}
 
-func TestSecondHandAt30Seconds(t *testing.T) {
+	t.Errorf(
-	tm := time.Date(1337, time.January, 1, 0, 0, 30, 0, time.UTC)
+		"Expected to find the second hand with x2 of %+v and y2 of %+v, in the SVG output %v",
-
+		x2,
-	want := Point{X: 150, Y: 150 + 90}
+		y2,
-	got := SecondHand(tm)
+		b.String(),
-
+	)
-	if got != want {
-		t.Errorf("Got %v, wanted %v", got, want)
-	}
 }

main.go

@@ -1,9 +1,7 @@
 package main
 
 import (
-	"fmt"
 	"gobytest/clockface"
-	"io"
 	"os"
 	"time"
 )
@@ -18,29 +16,5 @@ func main() {
 	// clockface
 	t := time.Now()
 
-	sh := clockface.SecondHand(t)
+	clockface.SVGWriter(os.Stdout, t)
-	io.WriteString(os.Stdout, svgStart)
-	io.WriteString(os.Stdout, bezel)
-	io.WriteString(os.Stdout, secondHandTag(sh))
-	io.WriteString(os.Stdout, svgEnd)
 }
-
-func secondHandTag(p clockface.Point) string {
-	return fmt.Sprintf(
-		`<line x1="150" y1="150" x2="%f" y2="%f" style="fill:none;stroke:#f00;stroke-width:3px;"/>`,
-		p.X,
-		p.Y,
-	)
-}
-
-const svgStart = `<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
-<svg xmlns="http://www.w3.org/2000/svg"
-     width="100%"
-     height="100%"
-     viewBox="0 0 300 300"
-     version="2.0">`
-
-const bezel = `<circle cx="150" cy="150" r="100" style="fill:#fff;stroke:#000;stroke-width:5px;"/>`
-
-const svgEnd = `</svg>`