template: Restructuring and adding tests.

4 files changed, 159 insertions, 73 deletions

diff --git a/internal/feed/template/funcs.go b/internal/feed/template/funcs.go
new file mode 100644
index 0000000..300b9ca
--- /dev/null
+++ b/internal/feed/template/funcs.go
@@ -0,0 +1,72 @@
+package template
+
+import (
+	"fmt"
+	html "html/template"
+	"strconv"
+	"strings"
+
+	"github.com/Necoro/feed2imap-go/pkg/log"
+)
+
+// dict creates a map out of the passed in key/value pairs.
+func dict(v ...interface{}) map[string]interface{} {
+	dict := make(map[string]interface{})
+	lenv := len(v)
+	for i := 0; i < lenv; i += 2 {
+		key := v[i].(string)
+		if i+1 >= lenv {
+			dict[key] = ""
+			continue
+		}
+		dict[key] = v[i+1]
+	}
+	return dict
+}
+
+// join takes a separator and a list of strings and puts the former in between each pair of the latter.
+func join(sep string, parts []string) string {
+	return strings.Join(parts, sep)
+}
+
+// lastUrlPart returns the last part of a URL string
+func lastUrlPart(url string) string {
+	split := strings.Split(url, "/")
+	return split[len(split)-1]
+}
+
+// byteCount receives an integer as a string, that is interpreted as a size in bytes.
+// This size is then equipped with the corresponding unit:
+//
+func byteCount(str string) string {
+	var b uint64
+	if str != "" {
+		var err error
+		if b, err = strconv.ParseUint(str, 10, 64); err != nil {
+			log.Printf("Cannot convert '%s' to byte count: %s", str, err)
+		}
+	}
+
+	const unit = 1024
+	if b < unit {
+		return fmt.Sprintf("%d B", b)
+	}
+	div, exp := uint64(unit), 0
+	for n := b / unit; n >= unit; n /= unit {
+		div *= unit
+		exp++
+	}
+	return fmt.Sprintf("%.1f %cB", float64(b)/float64(div), "KMGTPE"[exp])
+}
+
+func _html(s string) html.HTML {
+	return html.HTML(s)
+}
+
+var funcMap = map[string]interface{}{
+	"dict":        dict,
+	"join":        join,
+	"lastUrlPart": lastUrlPart,
+	"byteCount":   byteCount,
+	"html":        _html,
+}
diff --git a/internal/feed/template/funcs_test.go b/internal/feed/template/funcs_test.go
new file mode 100644
index 0000000..c75d27d
--- /dev/null
+++ b/internal/feed/template/funcs_test.go
@@ -0,0 +1,57 @@
+package template
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestByteCount(t *testing.T) {
+	tests := map[string]struct {
+		inp string
+		out string
+	}{
+		"Empty":        {"", "0 B"},
+		"Byte":         {"123", "123 B"},
+		"KByte":        {"2048", "2.0 KB"},
+		"KByte slight": {"2049", "2.0 KB"},
+		"KByte round":  {"2560", "2.5 KB"},
+		"MByte":        {"2097152", "2.0 MB"},
+	}
+
+	for name, tt := range tests {
+		t.Run(name, func(tst *testing.T) {
+			out := byteCount(tt.inp)
+
+			if diff := cmp.Diff(tt.out, out); diff != "" {
+				tst.Error(diff)
+			}
+		})
+	}
+}
+
+func TestDict(t *testing.T) {
+	type i []interface{}
+	type o map[string]interface{}
+
+	tests := map[string]struct {
+		inp i
+		out o
+	}{
+		"Empty": {i{}, o{}},
+		"One":   {i{"1"}, o{"1": ""}},
+		"Two":   {i{"1", 1}, o{"1": 1}},
+		"Three": {i{"1", "2", "3"}, o{"1": "2", "3": ""}},
+		"Four":  {i{"1", 2, "3", '4'}, o{"1": 2, "3": '4'}},
+	}
+
+	for name, tt := range tests {
+		t.Run(name, func(tst *testing.T) {
+			out := dict(tt.inp...)
+
+			if diff := cmp.Diff(tt.out, o(out)); diff != "" {
+				tst.Error(diff)
+			}
+		})
+	}
+}
diff --git a/internal/feed/template/template.go b/internal/feed/template/template.go
index 9804190..8b3fb73 100644
--- a/internal/feed/template/template.go
+++ b/internal/feed/template/template.go
@@ -2,96 +2,46 @@ package template
 
 import (
 	_ "embed"
-	"fmt"
 	html "html/template"
 	"io"
-	"strconv"
-	"strings"
 	text "text/template"
-
-	"github.com/Necoro/feed2imap-go/pkg/log"
 )
 
-type Template interface {
+type template interface {
 	Execute(wr io.Writer, data interface{}) error
 }
 
+type Template struct {
+	template
+	useHtml bool
+	dflt    string
+}
+
 //go:embed html.tpl
-var htmlTpl string
+var defaultHtmlTpl string
 
 //go:embed text.tpl
-var textTpl string
-
-var Html = fromString("Feed", htmlTpl, true)
-var Text = fromString("Feed", textTpl, false)
-
-func must(t Template, err error) Template {
-	if err != nil {
-		panic(err)
-	}
-	return t
-}
-
-func dict(v ...interface{}) map[string]interface{} {
-	dict := make(map[string]interface{})
-	lenv := len(v)
-	for i := 0; i < lenv; i += 2 {
-		key := v[i].(string)
-		if i+1 >= lenv {
-			dict[key] = ""
-			continue
-		}
-		dict[key] = v[i+1]
-	}
-	return dict
-}
+var defaultTextTpl string
 
-func join(sep string, parts []string) string {
-	return strings.Join(parts, sep)
+var Html = Template{
+	useHtml: true,
+	dflt:    defaultHtmlTpl,
 }
 
-func lastUrlPart(url string) string {
-	split := strings.Split(url, "/")
-	return split[len(split)-1]
+var Text = Template{
+	useHtml: false,
+	dflt:    defaultTextTpl,
 }
 
-func byteCount(str string) string {
-	var b uint64
-	if str != "" {
-		var err error
-		if b, err = strconv.ParseUint(str, 10, 64); err != nil {
-			log.Printf("Cannot convert '%s' to byte count: %s", str, err)
-		}
-	}
-
-	const unit = 1024
-	if b < unit {
-		return fmt.Sprintf("%d B", b)
-	}
-	div, exp := uint64(unit), 0
-	for n := b / unit; n >= unit; n /= unit {
-		div *= unit
-		exp++
+func (tpl *Template) loadDefault() {
+	if tpl.useHtml {
+		tpl.template = html.Must(html.New("Html").Funcs(funcMap).Parse(tpl.dflt))
+	} else {
+		tpl.template = text.Must(text.New("Text").Funcs(funcMap).Parse(tpl.dflt))
 	}
-	return fmt.Sprintf("%.1f %cB", float64(b)/float64(div), "KMGTPE"[exp])
-}
-
-func _html(s string) html.HTML {
-	return html.HTML(s)
-}
-
-var funcMap = html.FuncMap{
-	"dict":        dict,
-	"join":        join,
-	"lastUrlPart": lastUrlPart,
-	"byteCount":   byteCount,
-	"html":        _html,
 }
 
-func fromString(name, templateStr string, useHtml bool) Template {
-	if useHtml {
-		return must(html.New(name).Funcs(funcMap).Parse(templateStr))
-	} else {
-		return must(text.New(name).Funcs(text.FuncMap(funcMap)).Parse(templateStr))
-	}
+func init() {
+	Html.loadDefault()
+	Text.loadDefault()
 }
diff --git a/internal/feed/template/template_test.go b/internal/feed/template/template_test.go
new file mode 100644
index 0000000..c3fbb7a
--- /dev/null
+++ b/internal/feed/template/template_test.go
@@ -0,0 +1,7 @@
+package template
+
+import "testing"
+
+func TestTemplateDefaults(t *testing.T) {
+	// Dummy test to ensure init() works, i.e. the default templates are loaded
+}