feat: Improve error handling with custom error types and detailed messages

config/config_test.go

@@ -38,22 +38,56 @@ func TestGetConfig(t *testing.T) {
 
 func TestParsePositiveInt(t *testing.T) {
 	tests := []struct {
-		name    string
-		input   string
-		want    int
-		wantErr bool
+		name       string
+		param      string
+		input      string
+		want       int
+		wantErr    bool
+		errType    interface{}
+		errMessage string
 	}{
-		{"valid positive", "42", 42, false},
-		{"zero", "0", 0, true},
-		{"negative", "-1", 0, true},
-		{"invalid", "abc", 0, true},
+		{
+			name:    "valid positive",
+			param:   "TEST_PARAM",
+			input:   "42",
+			want:    42,
+			wantErr: false,
+		},
+		{
+			name:       "zero",
+			param:      "TEST_PARAM",
+			input:      "0",
+			wantErr:    true,
+			errType:    &ValidationError{},
+			errMessage: "invalid value '0' for TEST_PARAM: must be positive",
+		},
+		{
+			name:       "negative",
+			param:      "TEST_PARAM",
+			input:      "-1",
+			wantErr:    true,
+			errType:    &ValidationError{},
+			errMessage: "invalid value '-1' for TEST_PARAM: must be positive",
+		},
+		{
+			name:       "invalid",
+			param:      "TEST_PARAM",
+			input:      "abc",
+			wantErr:    true,
+			errType:    &ValidationError{},
+			errMessage: "invalid value 'abc' for TEST_PARAM: must be a valid integer",
+		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			got, err := parsePositiveInt(tt.input)
+			got, err := parsePositiveInt(tt.param, tt.input)
 			if tt.wantErr {
 				assert.Error(t, err)
+				assert.IsType(t, tt.errType, err)
+				if tt.errMessage != "" {
+					assert.Equal(t, tt.errMessage, err.Error())
+				}
 			} else {
 				assert.NoError(t, err)
 				assert.Equal(t, tt.want, got)
@@ -61,3 +95,52 @@ func TestParsePositiveInt(t *testing.T) {
 		})
 	}
 }
+
+func TestConfigValidation(t *testing.T) {
+	tests := []struct {
+		name       string
+		envVars    map[string]string
+		wantErr    bool
+		errMessage string
+	}{
+		{
+			name: "invalid log level",
+			envVars: map[string]string{
+				EnvLogLevel: "invalid",
+			},
+			wantErr:    true,
+			errMessage: "invalid value 'invalid' for LOG_LEVEL: must be one of: debug, info, warn, error",
+		},
+		{
+			name: "invalid worker count",
+			envVars: map[string]string{
+				EnvLogLevel:   "debug",
+				EnvRootPath:   ".",
+				EnvNumWorkers: "-1",
+			},
+			wantErr:    true,
+			errMessage: "invalid value '-1' for NUM_OF_WORKERS: must be positive",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Clear environment
+			os.Clearenv()
+
+			// Set required environment variables
+			for k, v := range tt.envVars {
+				os.Setenv(k, v)
+			}
+
+			// Defer cleanup
+			defer os.Clearenv()
+
+			if tt.wantErr {
+				assert.PanicsWithError(t, tt.errMessage, func() {
+					GetConfig()
+				})
+			}
+		})
+	}
+}