Big change

- Reorganised request template handling and error handling
- Added Content-Type response
- Implemented templating data
- Break out router

Makefile

@@ -16,7 +16,7 @@ clean:
 .PHONY: build
 build: datetime
 
-datetime: *.go
+datetime: *.go data/*.go
 	$(GO) build -tags "$(TAGS)" -v -o datetime
 
 .PHONY: test

app.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"html/template"
 	"net/http"
 
@@ -8,6 +9,9 @@ import (
 	"go.uber.org/zap"
 )
 
+// ErrNoTemplate is returned when a template was not found on the server
+var ErrNoTemplate = errors.New("missing template")
+
 // Datetime is the main application server
 type Datetime struct {
 	*http.ServeMux
@@ -19,7 +23,7 @@ type Datetime struct {
 // like templates and data exist
 func NewDatetime() (*Datetime, error) {
 	// Data
-	tmpl, err := template.ParseGlob("templates/*")
+	tmpl, err := template.New("templates").Funcs(templateFuncs).ParseGlob("templates/*")
 	if err != nil {
 		return nil, err
 	}
@@ -42,6 +46,11 @@ func NewDatetime() (*Datetime, error) {
 	return app, nil
 }
 
+type appRequest struct {
+	App Datetime
+	Req Request
+}
+
 // index handles all incoming page requests
 func (app Datetime) index(w http.ResponseWriter, req *http.Request) {
 	var err error
@@ -51,45 +60,29 @@ func (app Datetime) index(w http.ResponseWriter, req *http.Request) {
 		return
 	}
 
-	accept := req.Header.Get("Accept")
-	tmpl, acceptable := app.chooseTemplate(accept)
-	if !acceptable {
-		w.WriteHeader(http.StatusNotAcceptable)
-		return
-	}
+	tmpl := app.loadTemplate("index", w, req)
 	if tmpl == nil {
-		l.Error("unable to find template", zap.String("accept", accept))
-		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
-
 	if req.Method == http.MethodHead {
 		return
 	}
 
-	l.Debug("", zap.Reflect("url", req.URL))
-	err = tmpl.Execute(w, nil)
+	request := Request{}
+	if req.URL.Path != "/" {
+		request, err = ParseRequest(req.URL)
+		if err != nil {
+			l.Debug("parse failed", zap.Error(err))
+			app.error(HTTPError{http.StatusBadRequest, err}, w, req)
+			return
+		}
+	}
+
+	l.Debug("rendering template", zap.Reflect("request", request))
+	err = tmpl.Execute(w, appRequest{app, request})
 	if err != nil {
 		l.Error("templating failed", zap.Error(err))
-		w.WriteHeader(http.StatusInternalServerError) // Usually this will fail
+		app.templateError(HTTPError{http.StatusInternalServerError, err}, w, req)
 		return
 	}
 }
-
-// chooseTemplate returns a template based on the accepted mime types from the
-// client, and if a template cannot be found it returns a nil template.
-func (app Datetime) chooseTemplate(accept string) (t *template.Template, acceptable bool) {
-	responseType := chooseResponseType(accept)
-	templateName := ""
-	switch responseType {
-	case responsePlain:
-		templateName = "index.txt"
-	case responseHTML:
-		templateName = "index.html"
-	case responseAny:
-		templateName = "index.txt"
-	case responseUnknown:
-		return nil, false
-	}
-	return app.tmpl.Lookup(templateName), true
-}

app_test.go

@@ -7,27 +7,31 @@ import (
 )
 
 func TestChooseTemplate(t *testing.T) {
-	tmpl, err := template.ParseGlob("templates/*")
+	tmpl, err := template.New("templates").Funcs(templateFuncs).ParseGlob("templates/*")
 	if err != nil {
 		panic(err)
 	}
 	app := &Datetime{tmpl: tmpl}
 
 	type chooseTest struct {
-		accept     string
-		acceptable bool
-		template   string
+		accept      string
+		acceptable  bool
+		contentType string
+		template    string
 	}
 	tests := []chooseTest{
-		{"text/html", true, "index.html"},
-		{"text/html;q=0.9,text/plain", true, "index.txt"},
-		{"image/png", false, ""},
-		{"*/*", true, "index.txt"},
+		{"text/html", true, "text/html", "index.html"},
+		{"text/html;q=0.9,text/plain", true, "text/plain", "index.txt"},
+		{"image/png", false, "", ""},
+		{"*/*", true, "text/plain", "index.txt"},
 	}
 
 	for _, test := range tests {
-		tmpl, acceptable := app.chooseTemplate(test.accept)
+		tmpl, contentType, acceptable := app.chooseTemplate(test.accept, "index")
 		fn := fmt.Sprintf("chooseTemplate(\"%s\")", test.accept)
+		if contentType != test.contentType {
+			t.Errorf("%s; contentType = %v; wanted %v", fn, contentType, test.contentType)
+		}
 		if acceptable != test.acceptable {
 			t.Errorf("%s; acceptable = %v; wanted %v", fn, acceptable, test.acceptable)
 		}

data/data.go

@@ -3,6 +3,7 @@ package data
 import (
 	"encoding/json"
 	"io/ioutil"
+	"strings"
 )
 
 // ReadCities opens the file "data/cities.json" and reads it into a map
@@ -20,3 +21,15 @@ func ReadCities() (map[string]*City, error) {
 
 	return cities, nil
 }
+
+func extendName(names ...string) string {
+	return strings.Join(names, ", ")
+}
+
+// FullName returns a fully qualified human readable name
+func (c City) FullName() string {
+	if len(c.Admin1.Name) > 0 {
+		return extendName(c.Name, c.Admin1.Name, c.Country.Name)
+	}
+	return extendName(c.Name, c.Country.Name)
+}

data/types.go

@@ -1,6 +1,6 @@
 package data
 
-// city represents a city that belongs inside an administrative division level 1
+// City represents a city that belongs inside an administrative division level 1
 // and a country
 type City struct {
 	// Ref is the ASCII name of the city

error.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"net/http"
+
+	"go.uber.org/zap"
+)
+
+// HTTPError is an error that can be rendered into a HTML page to follow HTTP
+// status semantics
+type HTTPError struct {
+	Status int
+	Error  error
+}
+
+func (app Datetime) error(httpErr HTTPError, w http.ResponseWriter, req *http.Request) {
+	tmpl := app.loadTemplate("error", w, req)
+	if tmpl == nil {
+		return
+	}
+
+	w.WriteHeader(httpErr.Status)
+	if req.Method == http.MethodHead {
+		return
+	}
+
+	err := tmpl.Execute(w, httpErr)
+	if err != nil {
+		l.Error("template failed", zap.Error(err))
+		app.templateError(HTTPError{http.StatusInternalServerError, err}, w, req)
+		return
+	}
+}
+
+func (app Datetime) simpleError(httpErr HTTPError, w http.ResponseWriter, req *http.Request) {
+	w.Header().Set("Content-Type", "text/plain")
+
+	w.WriteHeader(httpErr.Status)
+	if req.Method == http.MethodHead {
+		return
+	}
+
+	if httpErr.Error != nil {
+		w.Write([]byte(http.StatusText(httpErr.Status) + ": " + httpErr.Error.Error()))
+	} else {
+		w.Write([]byte(http.StatusText(httpErr.Status)))
+	}
+}
+
+func (app Datetime) templateError(httpErr HTTPError, w http.ResponseWriter, req *http.Request) {
+	// Sadly, we probably already sent out the header
+	//w.Header().Set("Content-Type", "text/plain")
+	//w.WriteHeader(httpErr.Status)
+
+	if httpErr.Error != nil {
+		w.Write([]byte("\n" + http.StatusText(httpErr.Status) + ": " + httpErr.Error.Error()))
+	} else {
+		w.Write([]byte("\n" + http.StatusText(httpErr.Status)))
+	}
+}

logger_development.go

@@ -4,8 +4,11 @@ package main
 
 import (
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 )
 
 func zapConfig() zap.Config {
-	return zap.NewDevelopmentConfig()
+	dev := zap.NewDevelopmentConfig()
+	dev.EncoderConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder
+	return dev
 }

scripts/data.go

@@ -27,7 +27,7 @@ import (
 	"github.com/serverwentdown/datetime.link/data"
 )
 
-var regexName = regexp.MustCompile(`[^a-zA-Z1-9]+`)
+var regexName = regexp.MustCompile(`[^a-zA-Z1-9']+`)
 
 func extendRef(refs ...string) string {
 	return strings.Join(refs, "-")

template.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"html/template"
+	"net/http"
+
+	"go.uber.org/zap"
+)
+
+var templateFuncs = map[string]interface{}{
+	"statusText": templateFuncStatusText,
+	"thisIsSafe": templateFuncThisIsSafe,
+	// Formatting
+	"formatOffset": templateFuncFormatOffset,
+	// Logic
+	"resolveZone": templateFuncResolveZone,
+}
+
+func templateFuncStatusText(s int) string {
+	return http.StatusText(s)
+}
+func templateFuncThisIsSafe(s string) template.HTML {
+	return template.HTML(s)
+}
+
+func templateFuncFormatOffset(offset int) string {
+	return FormatZoneOffset(offset)
+}
+
+// ResolvedZone holds a resolved zone or an error
+type ResolvedZone struct {
+	Zone
+	Error error
+}
+
+func templateFuncResolveZone(app Datetime, zone string) ResolvedZone {
+	z, err := ResolveZone(app.cities, zone)
+	if err != nil {
+		l.Debug("unable to resolve zone", zap.Reflect("zone", zone), zap.Error(err))
+	}
+	return ResolvedZone{z, err}
+}
+
+// loadTemplate returns a matching template for the request. It also causes an
+// error if the template is not found or the Accept parameters are incorrect.
+func (app Datetime) loadTemplate(name string, w http.ResponseWriter, req *http.Request) *template.Template {
+	accept := req.Header.Get("Accept")
+	tmpl, contentType, acceptable := app.chooseTemplate(accept, name)
+	if !acceptable {
+		app.simpleError(HTTPError{http.StatusNotAcceptable, nil}, w, req)
+		return nil
+	}
+	if tmpl == nil {
+		l.Error("unable to find template", zap.String("name", name), zap.String("accept", accept))
+		app.simpleError(HTTPError{http.StatusInternalServerError, ErrNoTemplate}, w, req)
+		return nil
+	}
+	w.Header().Set("Content-Type", contentType)
+	return tmpl
+}
+
+// chooseTemplate returns a template based on the accepted mime types from the
+// client, and if a template cannot be found it returns a nil template.
+func (app Datetime) chooseTemplate(accept string, name string) (t *template.Template, contentType string, acceptable bool) {
+	acceptable = true
+	switch chooseResponseType(accept) {
+	case responsePlain:
+		t = app.tmpl.Lookup(name + ".txt")
+		contentType = "text/plain"
+	case responseHTML:
+		t = app.tmpl.Lookup(name + ".html")
+		contentType = "text/html"
+	case responseAny:
+		t = app.tmpl.Lookup(name + ".txt")
+		contentType = "text/plain"
+	case responseUnknown:
+		acceptable = false
+		return
+	}
+	return
+}

template_test.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestTemplateFuncFormatOffset(t *testing.T) {
+	want, got := "+06:06", templateFuncFormatOffset(6*60*60+6*60)
+	if want != got {
+		t.Fatalf("got offset %v, want offset %v", got, want)
+	}
+
+	want, got = "-12:15", templateFuncFormatOffset(-(12*60*60 + 15*60))
+	if want != got {
+		t.Fatalf("got offset %v, want offset %v", got, want)
+	}
+
+	want, got = "\u00B100:00", templateFuncFormatOffset(-(0*60*60 + 0*60))
+	if want != got {
+		t.Fatalf("got offset %v, want offset %v", got, want)
+	}
+
+	want, got = "+00:01", templateFuncFormatOffset(0*60*60+1*60)
+	if want != got {
+		t.Fatalf("got offset %v, want offset %v", got, want)
+	}
+}

templates/error.html

@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+	<meta charset="utf-8">
+	<title>{{.Status | statusText}} - datetime.link</title>
+	<meta name="viewport" content="width=device-width">
+	
+	{{template "resources.html"}}
+</head>
+<body>
+	{{template "resources-body.html"}}
+
+	<main id="app">
+		<h1 title="Status Code: {{.Status}}">{{.Status | statusText}}</h1>
+		{{if eq .Status 400}}
+		<p title="Error: {{.Error.Error}}">The URL path is not valid</p>
+		{{else}}
+		<p>{{.Error.Error}}</p>
+		{{end}}
+	</main>
+
+	{{template "footer.html"}}
+</body>
+</html>
+

templates/error.txt

@@ -0,0 +1,2 @@
+{{.Status}} {{.Status | statusText | thisIsSafe}}
+{{.Error | thisIsSafe}}

templates/footer.html

@@ -0,0 +1,11 @@
+<footer>
+	<ul class="list-inline">
+		<li><a href="https://github.com/serverwentdown/datetime.link" target="_blank">About datetime.link</a></li><!--
+		--><li><a href="https://github.com/serverwentdown/datetime.link/issues/new" target="_blank">Found a bug?</a></li><!--
+		--><li onclick="toggleTheme()"><!--
+			--><span class="icon theme-toggle-system">{{template "icon_solid_adjust.svg"}}</span><span class="theme-toggle-name theme-toggle-system">&nbsp;System theme</span><!--
+			--><span class="icon theme-toggle-dark">{{template "icon_solid_moon.svg"}}</span><span class="theme-toggle-name theme-toggle-dark">&nbsp;Dark theme</span><!--
+			--><span class="icon theme-toggle-light">{{template "icon_solid_sun.svg"}}</span><span class="theme-toggle-name theme-toggle-light">&nbsp;Light theme</span><!--
+		--></li>
+	</ul>
+</footer>

templates/index.html

@@ -4,13 +4,38 @@
 	<meta charset="utf-8">
 	<title>datetime.link</title>
 	<meta name="viewport" content="width=device-width">
-	
-	<link rel="stylesheet" href="https://rsms.me/inter/inter.css">
-	<link rel="stylesheet" href="/css/styles.css">
+
+	{{template "resources.html"}}
 </head>
 <body>
-	<script src="/js/theme.js"></script>
+	{{template "resources-body.html"}}
+
 	<main id="app">
+		{{$app := .App}}
+		{{$t := .Req.Time}}
+		{{range .Req.Zones}}
+			<d-zone zone="{{.}}">
+				{{with resolveZone $app .}}
+					{{if .Error}}
+						<d-zoneerror>
+							Unable to load zone. The URL path might not be valid
+						</d-zoneerror>
+					{{else}}
+						{{$zt := $t.In .Location}}
+						<d-zoneinfo>
+							<d-zonename>{{.Name}}</d-zonename>
+							{{if not .IsOffset}}
+								<d-zoneoffset>{{.TimeOffset $t | formatOffset}}</d-zoneoffset>
+							{{end}}
+							<d-date date="{{$zt.Format "2006-01-02"}}">{{$zt.Format "2006-01-02"}}</d-date>
+						</d-zoneinfo>
+						<d-zonefigure>
+							<d-time time="{{$zt.Format "15:04"}}">{{$zt.Format "15:04"}}</d-time>
+						</d-zonefigure>
+					{{end}}
+				{{end}}
+			</d-zone>
+		{{end}}
 		<!--
 		<d-zone>
 			<d-zoneinfo>
@@ -45,17 +70,7 @@
 		-->
 	</main>
 
-	<footer>
-		<ul class="list-inline">
-			<li><a href="https://github.com/serverwentdown/datetime.link" target="_blank">About datetime.link</a></li><!--
-			--><li><a href="https://github.com/serverwentdown/datetime.link/issues/new" target="_blank">Found a bug?</a></li><!--
-			--><li onclick="toggleTheme()"><!--
-				--><span class="icon theme-toggle-system">{{template "icon_solid_adjust.svg"}}</span><span class="theme-toggle-name theme-toggle-system">&nbsp;System theme</span><!--
-				--><span class="icon theme-toggle-dark">{{template "icon_solid_moon.svg"}}</span><span class="theme-toggle-name theme-toggle-dark">&nbsp;Dark theme</span><!--
-				--><span class="icon theme-toggle-light">{{template "icon_solid_sun.svg"}}</span><span class="theme-toggle-name theme-toggle-light">&nbsp;Light theme</span><!--
-			--></li>
-		</ul>
-	</footer>
+	{{template "footer.html"}}
 
 	<!-- Work in progress...
 	<script src="/js/third-party/luxon.min.js"></script>

templates/resources-body.html

@@ -0,0 +1 @@
+<script src="/js/theme.js"></script>

templates/resources.html

@@ -0,0 +1,2 @@
+<link rel="stylesheet" href="https://rsms.me/inter/inter.css">
+<link rel="stylesheet" href="/css/styles.css">

url.go

@@ -2,16 +2,20 @@ package main
 
 import (
 	"errors"
+	"fmt"
 	"net/url"
 	"strings"
 	"time"
 )
 
 // ErrMissingComponent is thrown when the URL has empty or missing components
-var ErrMissingComponent = errors.New("missing URL component")
+var ErrMissingComponent = errors.New("missing path component")
 
 // ErrTooManyComponent is thrown when there are more than 2 components
-var ErrTooManyComponent = errors.New("too many components")
+var ErrTooManyComponent = errors.New("too many path components")
+
+// ErrInvalidTime is thrown in a time.ParseError
+var ErrInvalidTime = errors.New("invalid ISO 8601 time")
 
 var timeRFC3339NoSec = "2006-01-02T15:04Z07:00"
 var timeFormats = []string{time.RFC3339, timeRFC3339NoSec}
@@ -47,7 +51,7 @@ func ParseRequest(u *url.URL) (Request, error) {
 		}
 	}
 	if err != nil {
-		return Request{}, err
+		return Request{}, fmt.Errorf("%w: %v", ErrInvalidTime, err)
 	}
 
 	// Split zones

url_test.go

@@ -25,7 +25,7 @@ func TestURLParse(t *testing.T) {
 		return
 	}
 	want := Request{
-		time.Date(2020, 6, 2, 14, 0, 0, 0, time.FixedZone("UTC +8", 8*60*60)),
+		time.Date(2020, time.June, 2, 14, 0, 0, 0, time.FixedZone("UTC +8", 8*60*60)),
 		[]string{"Singapore", "Malaysia"},
 	}
 	if !cmp.Equal(got, want) {
@@ -39,7 +39,7 @@ func TestURLParse(t *testing.T) {
 		return
 	}
 	want = Request{
-		time.Date(2019, 4, 30, 18, 0, 0, 0, time.FixedZone("UTC", 0)),
+		time.Date(2019, time.April, 30, 18, 0, 0, 0, time.FixedZone("UTC", 0)),
 		[]string{"Nowhere"},
 	}
 	if !cmp.Equal(got, want) {
@@ -74,15 +74,13 @@ func TestURLParseFail(t *testing.T) {
 
 	u = mustURLParse("http://test/2000-01-13T00:00Z08:00/hi")
 	_, err = ParseRequest(u)
-	_, isParseError := err.(*time.ParseError)
-	if !isParseError {
-		t.Errorf("got error %v, want time.ParseError", err)
+	if !errors.Is(err, ErrInvalidTime) {
+		t.Errorf("got error %v, want error %v", err, ErrInvalidTime)
 	}
 
 	u = mustURLParse("http://test/2000-01-13 00:00+08:00/hi")
 	_, err = ParseRequest(u)
-	_, isParseError = err.(*time.ParseError)
-	if !isParseError {
-		t.Errorf("got error %v, want time.ParseError", err)
+	if !errors.Is(err, ErrInvalidTime) {
+		t.Errorf("got error %v, want error %v", err, ErrInvalidTime)
 	}
 }

zone.go

@@ -2,11 +2,13 @@ package main
 
 import (
 	"errors"
+	"fmt"
 	"regexp"
 	"strconv"
 	"time"
 
 	"github.com/serverwentdown/datetime.link/data"
+	"go.uber.org/zap"
 )
 
 // ErrZoneNotFound is thrown when a zone string has no match
@@ -15,6 +17,9 @@ var ErrZoneNotFound = errors.New("zone not found")
 // ErrZoneOffsetInvalid is thrown when a zone string is an invalid zone offset
 var ErrZoneOffsetInvalid = errors.New("offset zone invalid")
 
+const zoneHour = 60 * 60
+const zoneMinute = 60
+
 var zoneOffsetRegexp = regexp.MustCompile(`^[+-][0-9]{2}:[0-9]{2}$`)
 
 // SearchCities looks up a city by it's reference
@@ -27,9 +32,9 @@ func SearchCities(cities map[string]*data.City, city string) (*data.City, error)
 }
 
 // ParseZoneOffset parses a zone string into a time.Location
-func ParseZoneOffset(zone string) (*time.Location, error) {
+func ParseZoneOffset(zone string) (int, error) {
 	if !zoneOffsetRegexp.MatchString(zone) {
-		return nil, ErrZoneOffsetInvalid
+		return 0, ErrZoneOffsetInvalid
 	}
 	// Assume that if it satisfies the regex, it satisfies the length and won't
 	// fail to parse
@@ -44,9 +49,26 @@ func ParseZoneOffset(zone string) (*time.Location, error) {
 	// Allow hour offsets greater that 24
 	m, _ := strconv.ParseUint(zone[1+3:1+3+2], 10, 64)
 	if m >= 60 {
-		return nil, ErrZoneOffsetInvalid
+		return 0, ErrZoneOffsetInvalid
 	}
-	return time.FixedZone("UTC"+zone, d*(int(h)*60*60+int(m)*60)), nil
+	offset := d * (int(h)*zoneHour + int(m)*zoneMinute)
+	return offset, nil
+}
+
+// FormatZoneOffset formats an offset into a string
+func FormatZoneOffset(offset int) string {
+	neg := offset < 0
+	s := '+'
+	if neg {
+		s = '-'
+		offset = -offset
+	}
+	if offset == 0 {
+		return "\u00B100:00"
+	}
+	h := offset / zoneHour
+	m := (offset % zoneHour) / zoneMinute
+	return fmt.Sprintf("%c%02d:%02d", s, h, m)
 }
 
 // Zone represents any form of zone offset: this could be a city or a fixed
@@ -58,13 +80,54 @@ type Zone struct {
 	Offset *time.Location
 }
 
+// IsOffset is true when the Zone is an offset instead of a city
+func (z Zone) IsOffset() bool {
+	return z.Offset != nil
+}
+
+// Name returns the name of the zone
+func (z Zone) Name() string {
+	if z.IsOffset() {
+		return z.Offset.String()
+	} else if z.City != nil {
+		return z.City.FullName()
+	}
+	return ""
+}
+
+// Location returns the time.Location of the zone. Useful for other functions
+func (z Zone) Location() *time.Location {
+	if z.IsOffset() {
+		return z.Offset
+	} else if z.City != nil {
+		loc, err := time.LoadLocation(z.City.Timezone)
+		if err != nil {
+			// This is a really bad situation
+			// TODO: validate this at boot time
+			l.Error("unable to find timezone", zap.String("timezone", z.City.Timezone))
+		}
+		return loc
+	}
+	return nil
+}
+
+// TimeOffset returns the timezone offset at a specific time
+func (z Zone) TimeOffset(t time.Time) int {
+	if l := z.Location(); l != nil {
+		_, offset := t.In(l).Zone()
+		return offset
+	}
+	return -1 // TODO: better invalid handling
+}
+
 // ResolveZone resolves a zone string into a Zone
 func ResolveZone(cities map[string]*data.City, zone string) (Zone, error) {
 	// Try parsing as a zone offset
 	offset, err := ParseZoneOffset(zone)
 	if err == nil {
+		offsetZone := time.FixedZone("UTC "+FormatZoneOffset(offset), offset)
 		return Zone{
-			Offset: offset,
+			Offset: offsetZone,
 		}, nil
 	}
 	// Parse as a city

zone_test.go

@@ -8,10 +8,51 @@ import (
 )
 
 func TestParseZoneOffset(t *testing.T) {
-	loc, err := ParseZoneOffset("+08:00")
+	offset, err := ParseZoneOffset("+08:00")
 	if err != nil {
 		t.Errorf("want error %v, got error %v", nil, err)
 	} else {
+		want := 8*60*60 + 0*60
+		if offset != want {
+			t.Errorf("got %d, want %d", offset, want)
+		}
+	}
+
+	offset, err = ParseZoneOffset("-01:30")
+	if err != nil {
+		t.Errorf("want error %v, got error %v", nil, err)
+	} else {
+		want := -(1*60*60 + 30*60)
+		if offset != want {
+			t.Errorf("got %d, want %d", offset, want)
+		}
+	}
+
+	_, err = ParseZoneOffset("-0030")
+	if err != ErrZoneOffsetInvalid {
+		t.Errorf("want error %v, got error %v", ErrZoneOffsetInvalid, err)
+	}
+
+	_, err = ParseZoneOffset("00:30")
+	if err != ErrZoneOffsetInvalid {
+		t.Errorf("want error %v, got error %v", ErrZoneOffsetInvalid, err)
+	}
+
+	_, err = ParseZoneOffset("+08:60")
+	if err != ErrZoneOffsetInvalid {
+		t.Errorf("want error %v, got error %v", ErrZoneOffsetInvalid, err)
+	}
+
+	_, err = ParseZoneOffset("+08:-6")
+	if err != ErrZoneOffsetInvalid {
+		t.Errorf("want error %v, got error %v", ErrZoneOffsetInvalid, err)
+	}
+
+	offset, err = ParseZoneOffset("+08:00")
+	if err != nil {
+		t.Errorf("want error %v, got error %v", nil, err)
+	} else {
+		loc := time.FixedZone("UTC "+FormatZoneOffset(offset), offset)
 		time := time.Date(2020, time.November, 8, 23, 9, 0, 0, loc).Unix()
 		want := int64(1604848140)
 		if time != want {
@@ -19,36 +60,17 @@ func TestParseZoneOffset(t *testing.T) {
 		}
 	}
 
-	loc, err = ParseZoneOffset("-00:30")
+	offset, err = ParseZoneOffset("-00:30")
 	if err != nil {
 		t.Errorf("want error %v, got error %v", nil, err)
 	} else {
+		loc := time.FixedZone("UTC "+FormatZoneOffset(offset), offset)
 		time := time.Date(2020, time.November, 8, 14, 39, 0, 0, loc).Unix()
 		want := int64(1604848140)
 		if time != want {
 			t.Errorf("got %d, want %d", time, want)
 		}
 	}
-
-	loc, err = ParseZoneOffset("-0030")
-	if err != ErrZoneOffsetInvalid {
-		t.Errorf("want error %v, got error %v", ErrZoneOffsetInvalid, err)
-	}
-
-	loc, err = ParseZoneOffset("00:30")
-	if err != ErrZoneOffsetInvalid {
-		t.Errorf("want error %v, got error %v", ErrZoneOffsetInvalid, err)
-	}
-
-	loc, err = ParseZoneOffset("+08:60")
-	if err != ErrZoneOffsetInvalid {
-		t.Errorf("want error %v, got error %v", ErrZoneOffsetInvalid, err)
-	}
-
-	loc, err = ParseZoneOffset("+08:-6")
-	if err != ErrZoneOffsetInvalid {
-		t.Errorf("want error %v, got error %v", ErrZoneOffsetInvalid, err)
-	}
 }
 
 func TestSearchCities(t *testing.T) {
@@ -109,9 +131,10 @@ func TestResolveZone(t *testing.T) {
 	if zone.City != nil {
 		t.Errorf("want City %v, got City %v", nil, zone.City)
 	}
-	wantOffset, _ := ParseZoneOffset("+04:00")
-	if zone.Offset.String() != wantOffset.String() {
-		t.Errorf("want Offset %v, got Offset %v", wantOffset, zone.Offset)
+	gotTime := time.Date(2020, time.January, 1, 0, 0, 0, 0, zone.Offset)
+	wantTime := time.Date(2019, time.December, 31, 20, 0, 0, 0, time.UTC)
+	if !gotTime.Equal(wantTime) {
+		t.Errorf("want time %v, got time %v", wantTime, gotTime)
 	}
 
 	zone, err = ResolveZone(cities, "+04:80")