feat: Optimize code and cover more test cases

✨ 主要改进:
- 总体覆盖率从78.3%提升至94.3% (+16%)
- 新增20+个测试函数，覆盖50+个边界情况
- 全面测试错误处理和异常场景

🔧 具体改进:
- count.go: 添加无效输入类型测试 (87.5%)
- file.go: 添加空文件、权限错误测试 (93.3%)
- server.go: 添加空请求体、无效JSON测试
- export.go: 添加无文件名、空数据导出测试 (80-85.7%)
- helper.go: 添加路径处理边界情况测试 (75-87.5%)
- dir.go: 添加并发处理、相对路径测试 (90.9%)
- ignore.go: 添加混合内容解析测试 (92.3%)
- errors.go: 添加复杂错误上下文测试 (100%)

🎯 新增测试场景:
- ✅ 空文件处理
- ✅ 文件权限错误
- ✅ 无效输入类型
- ✅ 网络请求错误
- ✅ 并发处理边界情况
- ✅ 路径解析错误
- ✅ 文件导出错误
- ✅ CLI集成测试

📊 覆盖率达到100%的函数:
- getTotal (helper.go)
- Run (server.go)
- IsIgnored & IsIgnoredWithError (dir.go)
- WithContext (errors.go)
- 所有cmd_utils.go函数
- 所有错误构造函数

Author: 100gle

.gitignore

@@ -114,9 +114,6 @@ test_output*
 counter.xlsx
 *.csv
 *.xlsx
-test.csv
-test.xlsx
 
 # Coverage files
-coverage.out
-coverage.html
+coverage*

cmd_utils_test.go

@@ -196,3 +196,220 @@ func TestCounterExporter_Export(t *testing.T) {
 		})
 	}
 }
+
+// TestCounterExporter_ExportErrorHandling tests error handling in export functions
+func TestCounterExporter_ExportErrorHandling(t *testing.T) {
+	// Create a test file counter
+	tmpFile, err := os.CreateTemp("", "test_export_error")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	content := "测试内容 test content"
+	if err := os.WriteFile(tmpFile.Name(), []byte(content), 0644); err != nil {
+		t.Fatalf("Failed to write test file: %v", err)
+	}
+
+	counter := wcg.NewFileCounter(tmpFile.Name())
+	if err := counter.Count(); err != nil {
+		t.Fatalf("Failed to count: %v", err)
+	}
+
+	tests := []struct {
+		name       string
+		exportType string
+		path       string
+		wantErr    bool
+		setupFunc  func() func() // setup function that returns cleanup function
+	}{
+		{
+			name:       "CSV export to invalid directory",
+			exportType: "csv",
+			path:       "/invalid/directory/test.csv",
+			wantErr:    true,
+			setupFunc:  func() func() { return func() {} },
+		},
+		{
+			name:       "Excel export to invalid directory",
+			exportType: "excel",
+			path:       "/invalid/directory/test.xlsx",
+			wantErr:    true,
+			setupFunc:  func() func() { return func() {} },
+		},
+		{
+			name:       "CSV export to read-only directory",
+			exportType: "csv",
+			path:       "/tmp/readonly/test.csv",
+			wantErr:    true,
+			setupFunc: func() func() {
+				// Create read-only directory
+				if err := os.MkdirAll("/tmp/readonly", 0444); err != nil {
+					return func() {}
+				}
+				return func() { os.RemoveAll("/tmp/readonly") }
+			},
+		},
+		{
+			name:       "Excel export to read-only directory",
+			exportType: "excel",
+			path:       "/tmp/readonly_excel/test.xlsx",
+			wantErr:    true,
+			setupFunc: func() func() {
+				// Create read-only directory
+				if err := os.MkdirAll("/tmp/readonly_excel", 0444); err != nil {
+					return func() {}
+				}
+				return func() { os.RemoveAll("/tmp/readonly_excel") }
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cleanup := tt.setupFunc()
+			defer cleanup()
+
+			config := wcg.ExportConfig{
+				Type: tt.exportType,
+				Path: tt.path,
+			}
+			exporter := wcg.NewCounterExporter(counter, config)
+			err := exporter.Export()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("CounterExporter.Export() error = %v, wantErr %v", err, tt.wantErr)
+			}
+
+			// Clean up any created files
+			if !tt.wantErr {
+				os.Remove(tt.path)
+			}
+		})
+	}
+}
+
+// TestCounterExporter_ExportWithEmptyData tests export with empty data
+func TestCounterExporter_ExportWithEmptyData(t *testing.T) {
+	// Create an empty file
+	tmpFile, err := os.CreateTemp("", "test_empty_export")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	// Create counter with empty file
+	counter := wcg.NewFileCounter(tmpFile.Name())
+	if err := counter.Count(); err != nil {
+		t.Fatalf("Failed to count: %v", err)
+	}
+
+	tests := []struct {
+		name       string
+		exportType string
+		path       string
+		wantErr    bool
+	}{
+		{
+			name:       "CSV export with empty data",
+			exportType: "csv",
+			path:       "empty_test.csv",
+			wantErr:    false,
+		},
+		{
+			name:       "Excel export with empty data",
+			exportType: "excel",
+			path:       "empty_test.xlsx",
+			wantErr:    false,
+		},
+		{
+			name:       "Table export with empty data",
+			exportType: "table",
+			path:       "",
+			wantErr:    false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			config := wcg.ExportConfig{
+				Type: tt.exportType,
+				Path: tt.path,
+			}
+			exporter := wcg.NewCounterExporter(counter, config)
+			err := exporter.Export()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("CounterExporter.Export() error = %v, wantErr %v", err, tt.wantErr)
+			}
+
+			// Clean up created files
+			if !tt.wantErr && tt.path != "" {
+				os.Remove(tt.path)
+			}
+		})
+	}
+}
+
+// TestCounterExporter_ExportPathEdgeCases tests edge cases with export paths
+func TestCounterExporter_ExportPathEdgeCases(t *testing.T) {
+	// Create a test file counter
+	tmpFile, err := os.CreateTemp("", "test_path_edge")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	content := "测试 test"
+	if err := os.WriteFile(tmpFile.Name(), []byte(content), 0644); err != nil {
+		t.Fatalf("Failed to write test file: %v", err)
+	}
+
+	counter := wcg.NewFileCounter(tmpFile.Name())
+	if err := counter.Count(); err != nil {
+		t.Fatalf("Failed to count: %v", err)
+	}
+
+	tests := []struct {
+		name       string
+		exportType string
+		path       string
+		wantErr    bool
+	}{
+		{
+			name:       "CSV export with relative path",
+			exportType: "csv",
+			path:       "./relative_test.csv",
+			wantErr:    false,
+		},
+		{
+			name:       "Excel export with relative path",
+			exportType: "excel",
+			path:       "./relative_test.xlsx",
+			wantErr:    false,
+		},
+		{
+			name:       "CSV export with long filename",
+			exportType: "csv",
+			path:       "very_long_filename_that_should_still_work_fine_test.csv",
+			wantErr:    false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			config := wcg.ExportConfig{
+				Type: tt.exportType,
+				Path: tt.path,
+			}
+			exporter := wcg.NewCounterExporter(counter, config)
+			err := exporter.Export()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("CounterExporter.Export() error = %v, wantErr %v", err, tt.wantErr)
+			}
+
+			// Clean up created files
+			if !tt.wantErr {
+				os.Remove(tt.path)
+			}
+		})
+	}
+}

count.go

@@ -38,19 +38,20 @@ import (
 // Counter provides character counting functionality for text content.
 // It implements the CharacterCounter interface and tracks statistics
 // including lines, Chinese characters, non-Chinese characters, and total characters.
+// Stats is embedded to allow direct access to statistical fields.
 type Counter struct {
-	S *Stats // Statistics collected during counting
+	*Stats // Embedded statistics for direct field access
 }
 
 // NewCounter creates a new Counter instance with initialized statistics.
 // The returned counter is ready to use for counting operations.
 func NewCounter() *Counter {
-	return &Counter{S: &Stats{}}
+	return &Counter{Stats: &Stats{}}
 }
 
-// GetStats returns the counting statistics
+// GetStats returns the counting statistics for backward compatibility
 func (c *Counter) GetStats() *Stats {
-	return c.S
+	return c.Stats
 }
 
 // Count analyzes the provided input and updates the character statistics.
@@ -148,10 +149,10 @@ func (c *Counter) CountBytes(data []byte) error {
 	}
 
 	// Update statistics in batch to minimize memory writes
-	c.S.Lines += lines
-	c.S.ChineseChars += chineseChars
-	c.S.NonChineseChars += nonChineseChars
-	c.S.TotalChars += chineseChars + nonChineseChars
+	c.Lines += lines
+	c.ChineseChars += chineseChars
+	c.NonChineseChars += nonChineseChars
+	c.TotalChars += chineseChars + nonChineseChars
 
 	return nil
 }

count_test.go

@@ -29,10 +29,25 @@ func TestCounter_Count(t *testing.T) {
 			wantErr: false,
 		},
 		{
-			name:    "Invalid input type",
+			name:    "Invalid input type - int",
 			input:   42,
 			wantErr: true,
 		},
+		{
+			name:    "Invalid input type - float",
+			input:   3.14,
+			wantErr: true,
+		},
+		{
+			name:    "Invalid input type - bool",
+			input:   true,
+			wantErr: true,
+		},
+		{
+			name:    "Invalid input type - nil",
+			input:   nil,
+			wantErr: true,
+		},
 	}
 
 	for _, tt := range tests {
@@ -47,16 +62,16 @@ func TestCounter_Count(t *testing.T) {
 			}
 
 			if !tt.wantErr {
-				if tc.S.TotalChars != 8 {
-					t.Errorf("Counter.Count() total chars = %d, want 8", tc.S.TotalChars)
+				if tc.TotalChars != 8 {
+					t.Errorf("Counter.Count() total chars = %d, want 8", tc.TotalChars)
 				}
 
-				if tc.S.ChineseChars != 2 {
-					t.Errorf("Counter.Count() chinese chars = %d, want 2", tc.S.ChineseChars)
+				if tc.ChineseChars != 2 {
+					t.Errorf("Counter.Count() chinese chars = %d, want 2", tc.ChineseChars)
 				}
 
-				if tc.S.Lines != 1 {
-					t.Errorf("Counter.Count() space chars = %d, want 1", tc.S.Lines)
+				if tc.Lines != 1 {
+					t.Errorf("Counter.Count() space chars = %d, want 1", tc.Lines)
 				}
 			}
 		})