1 files changed, 124 insertions, 0 deletions
diff --git a/internal/vocab/reader_test.go b/internal/vocab/reader_test.go
new file mode 100644
index 0000000..ad43a07
--- /dev/null
+++ b/internal/vocab/reader_test.go
@@ -0,0 +1,124 @@
+package vocab
+
+import (
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+)
+
+func TestReadVocabularyFile(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name        string
+		fileContent string
+		want        []WordEntry
+	}{
+		{
+			name:        "empty file",
+			fileContent: "",
+			want:        nil,
+		},
+		{
+			name:        "words with translations",
+			fileContent: "ябълка = apple\nкотка = cat\nкуче = dog",
+			want: []WordEntry{
+				{Word: "ябълка", Translation: "apple", NeedsTranslation: false, CardType: CardTypeTranslation},
+				{Word: "котка", Translation: "cat", NeedsTranslation: false, CardType: CardTypeTranslation},
+				{Word: "куче", Translation: "dog", NeedsTranslation: false, CardType: CardTypeTranslation},
+			},
+		},
+		{
+			name: "mixed format",
+			fileContent: `ябълка
+котка = cat
+куче
+хляб = bread`,
+			want: []WordEntry{
+				{Word: "ябълка", Translation: "", NeedsTranslation: false, CardType: CardTypeTranslation},
+				{Word: "котка", Translation: "cat", NeedsTranslation: false, CardType: CardTypeTranslation},
+				{Word: "куче", Translation: "", NeedsTranslation: false, CardType: CardTypeTranslation},
+				{Word: "хляб", Translation: "bread", NeedsTranslation: false, CardType: CardTypeTranslation},
+			},
+		},
+		{
+			name:        "windows line endings",
+			fileContent: "ябълка\r\nкотка = cat\r\nкуче",
+			want: []WordEntry{
+				{Word: "ябълка", Translation: "", NeedsTranslation: false, CardType: CardTypeTranslation},
+				{Word: "котка", Translation: "cat", NeedsTranslation: false, CardType: CardTypeTranslation},
+				{Word: "куче", Translation: "", NeedsTranslation: false, CardType: CardTypeTranslation},
+			},
+		},
+		{
+			name:        "multiple equals signs",
+			fileContent: "test = word = with = equals",
+			want: []WordEntry{
+				{Word: "test", Translation: "word = with = equals", NeedsTranslation: false, CardType: CardTypeTranslation},
+			},
+		},
+		{
+			name: "english only format",
+			fileContent: `= apple
+= cat
+= dog`,
+			want: []WordEntry{
+				{Word: "", Translation: "apple", NeedsTranslation: true, CardType: CardTypeTranslation},
+				{Word: "", Translation: "cat", NeedsTranslation: true, CardType: CardTypeTranslation},
+				{Word: "", Translation: "dog", NeedsTranslation: true, CardType: CardTypeTranslation},
+			},
+		},
+		{
+			name: "word definition format",
+			fileContent: `ябълка == плод
+котка == домашно животно`,
+			want: []WordEntry{
+				{Word: "ябълка", Translation: "плод", NeedsTranslation: false, CardType: CardTypeDefinition},
+				{Word: "котка", Translation: "домашно животно", NeedsTranslation: false, CardType: CardTypeDefinition},
+			},
+		},
+		{
+			name: "mixed formats",
+			fileContent: `ябълка = apple
+котка == домашно животно
+= dog
+стол`,
+			want: []WordEntry{
+				{Word: "ябълка", Translation: "apple", NeedsTranslation: false, CardType: CardTypeTranslation},
+				{Word: "котка", Translation: "домашно животно", NeedsTranslation: false, CardType: CardTypeDefinition},
+				{Word: "", Translation: "dog", NeedsTranslation: true, CardType: CardTypeTranslation},
+				{Word: "стол", Translation: "", NeedsTranslation: false, CardType: CardTypeTranslation},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			tmpDir := t.TempDir()
+			tmpFile := filepath.Join(tmpDir, "vocab.txt")
+			if err := os.WriteFile(tmpFile, []byte(tt.fileContent), 0o644); err != nil {
+				t.Fatalf("write temp file: %v", err)
+			}
+
+			got, err := ReadVocabularyFile(tmpFile)
+			if err != nil {
+				t.Fatalf("ReadVocabularyFile() error = %v", err)
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Fatalf("ReadVocabularyFile() = %#v, want %#v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestReadVocabularyFile_FileNotFound(t *testing.T) {
+	t.Parallel()
+
+	_, err := ReadVocabularyFile("/nonexistent/file.txt")
+	if err == nil {
+		t.Fatal("expected error for non-existent file")
+	}
+}