rescribe: move getBookIdFromUrl() to gbook.go, and add tests for it

3 files changed, 78 insertions, 47 deletions

diff --git a/cmd/rescribe/gbook.go b/cmd/rescribe/gbook.go
index f0e9e1e..fe2f4b8 100644
--- a/cmd/rescribe/gbook.go
+++ b/cmd/rescribe/gbook.go
@@ -14,6 +14,7 @@ import (
 	"os"
 	"os/exec"
 	"path"
+	"regexp"
 	"strings"
 	"unicode"
 
@@ -206,3 +207,49 @@ func getGoogleBook(ctx context.Context, gbookcmd string, id string, basedir stri
 
 	return dir, nil
 }
+
+// getBookIdFromUrl returns a 12 character Google Book ID from
+// a Google URL, or an error if one can't be found.
+// Example URLs:
+// https://books.google.it/books?id=QjQepCuN8JYC
+// https://www.google.it/books/edition/_/VJbr-Oe2au0C
+func getBookIdFromUrl(url string) (string, error) {
+	lurl := strings.ToLower(url)
+	if len(url) == 12 && !strings.ContainsAny(url, "?/:") {
+		return url, nil
+	}
+
+	matchUrl, err := regexp.MatchString("https://www.google.[^\\/]*/books/", url)
+	if err != nil {
+		return "", err
+	}
+
+	if strings.HasPrefix(lurl, "https://books.google") {
+		start := strings.Index(lurl, "?id=")
+		if start == -1 {
+			start = strings.Index(lurl, "&id=")
+		}
+
+		if start >= 0 {
+			start += 4
+			if len(url[start:]) < 12 {
+				return "", fmt.Errorf("Could not find book ID in URL")
+			}
+			return url[start : start+12], nil
+		}
+
+		return "", fmt.Errorf("Could not find book ID in URL")
+	}
+	if matchUrl == true {
+		start := strings.Index(lurl, "edition/_/")
+
+		if start >= 0 {
+			start += 10
+			if len(url[start:]) < 12 {
+				return "", fmt.Errorf("Could not find book ID in URL")
+			}
+			return url[start : start+12], nil
+		}
+	}
+	return "", fmt.Errorf("Could not find book ID in URL")
+}
diff --git a/cmd/rescribe/gbook_test.go b/cmd/rescribe/gbook_test.go
new file mode 100644
index 0000000..6cd5a63
--- /dev/null
+++ b/cmd/rescribe/gbook_test.go
@@ -0,0 +1,31 @@
+// Copyright 2022 Nick White.
+// Use of this source code is governed by the GPLv3
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"testing"
+)
+
+func Test_getBookIdFromUrl(t *testing.T) {
+	cases := []struct {
+		url string
+		id string
+	}{
+		{"https://books.google.it/books?id=QjQepCuN8JYC", "QjQepCuN8JYC"},
+		{"https://www.google.it/books/edition/_/VJbr-Oe2au0C", "VJbr-Oe2au0C"},
+	}
+
+	for _, c := range cases {
+		t.Run(c.url, func(t *testing.T) {
+			id, err := getBookIdFromUrl(c.url)
+			if err != nil {
+				t.Fatalf("Error running test: %v", err)
+			}
+			if id != c.id {
+				t.Fatalf("Expected %s, got %s", c.id, id)
+			}
+		})
+	}
+}
diff --git a/cmd/rescribe/gui.go b/cmd/rescribe/gui.go
index a75b816..a9d5fbb 100644
--- a/cmd/rescribe/gui.go
+++ b/cmd/rescribe/gui.go
@@ -13,7 +13,6 @@ import (
 	"log"
 	"os"
 	"path/filepath"
-	"regexp"
 	"strings"
 
 	"fyne.io/fyne/v2"
@@ -43,52 +42,6 @@ var trainingNames = map[string]string{
 	"rescribev8_fast":    "Latin (early printing)",
 }
 
-// getBookIdFromUrl returns a 12 character Google Book ID from
-// a Google URL, or an error if one can't be found.
-// Example URLs:
-// https://books.google.it/books?id=QjQepCuN8JYC
-// https://www.google.it/books/edition/_/VJbr-Oe2au0C
-func getBookIdFromUrl(url string) (string, error) {
-	lurl := strings.ToLower(url)
-	if len(url) == 12 && !strings.ContainsAny(url, "?/:") {
-		return url, nil
-	}
-
-	matchUrl, err := regexp.MatchString("https://www.google.[^\\/]*/books/", url)
-	if err != nil {
-		return "", err
-	}
-
-	if strings.HasPrefix(lurl, "https://books.google") {
-		start := strings.Index(lurl, "?id=")
-		if start == -1 {
-			start = strings.Index(lurl, "&id=")
-		}
-
-		if start >= 0 {
-			start += 4
-			if len(url[start:]) < 12 {
-				return "", fmt.Errorf("Could not find book ID in URL")
-			}
-			return url[start : start+12], nil
-		}
-
-		return "", fmt.Errorf("Could not find book ID in URL")
-	}
-	if matchUrl == true {
-		start := strings.Index(lurl, "edition/_/")
-
-		if start >= 0 {
-			start += 10
-			if len(url[start:]) < 12 {
-				return "", fmt.Errorf("Could not find book ID in URL")
-			}
-			return url[start : start+12], nil
-		}
-	}
-	return "", fmt.Errorf("Could not find book ID in URL")
-}
-
 // copyStdoutToChan creates a pipe to copy anything written
 // to the file also to a rune channel.
 func copyStdoutToChan() (chan rune, error) {