refactor: Add config validation, defaults, and unit tests

config/config.go

@@ -18,6 +18,15 @@ const (
 	EnvResponseTimeout = "RESPONSE_TIMEOUT"
 )
 
+// Default configuration values
+const (
+	DefaultLogLevel        = zerolog.InfoLevel
+	DefaultNumWorkers      = 5
+	DefaultWorkerBatchSize = 100
+	DefaultMaxResponseSize = 1048576 // 1MB
+	DefaultResponseTimeout = 30      // seconds
+)
+
 // Config holds the application configuration loaded from environment variables
 type Config struct {
 	LogLevel        zerolog.Level // Logging level (debug, info, warn, error)
@@ -28,6 +37,14 @@ type Config struct {
 	WorkerBatchSize int          // Batch size for worker processing
 }
 
+// String returns a string representation of the configuration
+func (c *Config) String() string {
+	return fmt.Sprintf(
+		"Config{LogLevel: %s, RootPath: %s, MaxResponseSize: %d, NumWorkers: %d, ResponseTimeout: %d, WorkerBatchSize: %d}",
+		c.LogLevel, c.RootPath, c.MaxResponseSize, c.NumOfWorkers, c.ResponseTimeout, c.WorkerBatchSize,
+	)
+}
+
 var CONFIG Config
 
 // parsePositiveInt parses and validates positive integer values
@@ -57,6 +74,9 @@ func GetConfig() *Config {
 			return nil
 		},
 		EnvRootPath: func(v string) error {
+			if _, err := os.Stat(v); err != nil {
+				return fmt.Errorf("invalid root path: %w", err)
+			}
 			config.RootPath = v
 			return nil
 		},

config/config_test.go

@@ -0,0 +1,63 @@
+package config
+
+import (
+	"os"
+	"testing"
+
+	"github.com/rs/zerolog"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetConfig(t *testing.T) {
+	// Set up test environment variables
+	envVars := map[string]string{
+		EnvLogLevel:        "debug",
+		EnvRootPath:        ".",
+		EnvNumWorkers:      "5",
+		EnvWorkerBatchSize: "100",
+		EnvMaxResponseSize: "1048576",
+		EnvResponseTimeout: "30",
+	}
+
+	for k, v := range envVars {
+		os.Setenv(k, v)
+		defer os.Unsetenv(k)
+	}
+
+	// Get configuration
+	config := GetConfig()
+
+	// Assert configuration values
+	assert.Equal(t, zerolog.DebugLevel, config.LogLevel)
+	assert.Equal(t, ".", config.RootPath)
+	assert.Equal(t, 5, config.NumOfWorkers)
+	assert.Equal(t, 100, config.WorkerBatchSize)
+	assert.Equal(t, 1048576, config.MaxResponseSize)
+	assert.Equal(t, 30, config.ResponseTimeout)
+}
+
+func TestParsePositiveInt(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		want    int
+		wantErr bool
+	}{
+		{"valid positive", "42", 42, false},
+		{"zero", "0", 0, true},
+		{"negative", "-1", 0, true},
+		{"invalid", "abc", 0, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := parsePositiveInt(tt.input)
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.want, got)
+			}
+		})
+	}
+}