fix: trim space from bearer token; return error when token is empty; add tests

Author: roman-vanesyan

token/token.go

@@ -6,7 +6,7 @@ import (
 )
 
 var (
-	ErrMalformedToken = errors.New("token: invalid format")
+	ErrMalformedToken = errors.New("foundations/token: invalid format")
 )
 
 // TokenFromBearerString returns the token from a bearer token string.
@@ -15,5 +15,10 @@ func TokenFromBearerString(str string) (string, error) {
 		return "", ErrMalformedToken
 	}
 
-	return strings.TrimPrefix(strings.TrimSpace(str), "Bearer "), nil
+	tok := strings.TrimSpace(strings.TrimPrefix(str, "Bearer "))
+	if tok == "" {
+		return "", ErrMalformedToken
+	}
+
+	return tok, nil
 }

token/token_test.go

@@ -0,0 +1,73 @@
+package token
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTokenFromBearerString(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		want    string
+		wantErr bool
+	}{
+		{
+			name:    "Valid bearer token",
+			input:   "Bearer abc123",
+			want:    "abc123",
+			wantErr: false,
+		},
+		{
+			name:    "Valid bearer token with spaces",
+			input:   "Bearer   xyz789   ",
+			want:    "xyz789",
+			wantErr: false,
+		},
+		{
+			name:    "Missing 'Bearer' prefix",
+			input:   "abc123",
+			want:    "",
+			wantErr: true,
+		},
+		{
+			name:    "Empty string",
+			input:   "",
+			want:    "",
+			wantErr: true,
+		},
+		{
+			name:    "Only 'Bearer' without token",
+			input:   "Bearer ",
+			want:    "",
+			wantErr: true,
+		},
+		{
+			name:    "Lowercase 'bearer'",
+			input:   "bearer abc123",
+			want:    "",
+			wantErr: true,
+		},
+		{
+			name:    "Token with spaces",
+			input:   "Bearer abc 123 xyz",
+			want:    "abc 123 xyz",
+			wantErr: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := TokenFromBearerString(tt.input)
+
+			if tt.wantErr {
+				assert.Error(t, err)
+				assert.Empty(t, got)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.want, got)
+			}
+		})
+	}
+}