feat: add config package with env-var loading

internal/config/config_test.go

@@ -0,0 +1,36 @@
+package config_test
+
+import (
+	"testing"
+
+	"github.com/mathiasbq/supervisor/internal/config"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestLoadDefaults(t *testing.T) {
+	t.Setenv("SUPERVISOR_PORT", "")
+	t.Setenv("LITELLM_BASE_URL", "")
+	t.Setenv("LITELLM_API_KEY", "")
+	t.Setenv("SUPERVISOR_CONFIG_DIR", "")
+
+	cfg, err := config.Load()
+	require.NoError(t, err)
+	assert.Equal(t, "3200", cfg.Port)
+	assert.Equal(t, "http://iguana:4000", cfg.LiteLLMBaseURL)
+	assert.Equal(t, "./config/supervisor", cfg.ConfigDir)
+}
+
+func TestLoadFromEnv(t *testing.T) {
+	t.Setenv("SUPERVISOR_PORT", "4000")
+	t.Setenv("LITELLM_BASE_URL", "http://localhost:4000")
+	t.Setenv("LITELLM_API_KEY", "test-key")
+	t.Setenv("SUPERVISOR_CONFIG_DIR", "/etc/supervisor")
+
+	cfg, err := config.Load()
+	require.NoError(t, err)
+	assert.Equal(t, "4000", cfg.Port)
+	assert.Equal(t, "http://localhost:4000", cfg.LiteLLMBaseURL)
+	assert.Equal(t, "test-key", cfg.LiteLLMAPIKey)
+	assert.Equal(t, "/etc/supervisor", cfg.ConfigDir)
+}