test: improve coverage for ReadSingleConfig

Author: soulteary

internal/fn/scanner.go

@@ -140,18 +140,16 @@ func ReadSingleConfig(path string) *ConfigFile {
 		}
 
 		parts := strings.Fields(line)
-		if len(parts) < 2 {
-			continue
-		}
-
-		key := strings.ToLower(parts[0])
-		value := strings.Join(parts[1:], " ")
+		if len(parts) == 2 {
+			key := strings.ToLower(parts[0])
+			value := strings.Join(parts[1:], " ")
 
-		if key == "host" {
-			currentHost = value
-			config.Hosts[currentHost] = make(map[string]string)
-		} else if currentHost != "" {
-			config.Hosts[currentHost][key] = value
+			if key == "host" {
+				currentHost = value
+				config.Hosts[currentHost] = make(map[string]string)
+			} else if currentHost != "" {
+				config.Hosts[currentHost][key] = value
+			}
 		}
 	}
 

internal/fn/scanner_test.go

@@ -1,9 +1,11 @@
 package fn_test
 
 import (
+	"bufio"
 	"os"
 	"path/filepath"
 	"reflect"
+	"strings"
 	"testing"
 
 	"github.com/soulteary/ssh-config/internal/fn"
@@ -411,3 +413,33 @@ Nothing to see here`,
 		})
 	}
 }
+
+// TestReadSingleConfig_ScannerError tests the scanner error handling
+func TestReadSingleConfig_ScannerError(t *testing.T) {
+	// 创建一个包含无效数据的文件
+	tmpfile, err := os.CreateTemp("", "test_config_*.txt")
+	if err != nil {
+		t.Fatalf("Failed to create temporary file: %v", err)
+	}
+	defer os.Remove(tmpfile.Name())
+
+	// 写入一些正常数据和一个超长行来触发 scanner 错误
+	longLine := strings.Repeat("a", bufio.MaxScanTokenSize+1)
+	content := "Host testhost\n" + longLine
+
+	if _, err := tmpfile.WriteString(content); err != nil {
+		t.Fatalf("Failed to write to temp file: %v", err)
+	}
+
+	if err := tmpfile.Close(); err != nil {
+		t.Fatalf("Failed to close temp file: %v", err)
+	}
+
+	// 测试 ReadSingleConfig
+	result := fn.ReadSingleConfig(tmpfile.Name())
+
+	// 验证当发生扫描错误时返回 nil
+	if result != nil {
+		t.Errorf("Expected nil result when scanner error occurs, got: %v", result)
+	}
+}