first commit. added CI, Docker compose, blank client and server. used unit tests, they pass

server/internal/platform/config/config_test.go

@@ -0,0 +1,49 @@
+package config
+
+import (
+	"testing"
+)
+
+func TestLoadDefaults(t *testing.T) {
+	t.Setenv("MESSENGER_HTTP_ADDR", "")
+	t.Setenv("MESSENGER_ENV", "")
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+	if cfg.HTTPAddr != ":8080" {
+		t.Errorf("HTTPAddr = %q, want %q", cfg.HTTPAddr, ":8080")
+	}
+	if cfg.Environment != "development" {
+		t.Errorf("Environment = %q, want development", cfg.Environment)
+	}
+}
+
+func TestLoadFromEnv(t *testing.T) {
+	t.Setenv("MESSENGER_HTTP_ADDR", ":9000")
+	t.Setenv("MESSENGER_ENV", "production")
+	t.Setenv("MESSENGER_ALLOWED_ORIGINS", "https://a.example, https://b.example")
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+	if cfg.HTTPAddr != ":9000" {
+		t.Errorf("HTTPAddr = %q, want :9000", cfg.HTTPAddr)
+	}
+	if cfg.Environment != "production" {
+		t.Errorf("Environment = %q, want production", cfg.Environment)
+	}
+	if len(cfg.AllowedOrigins) != 2 || cfg.AllowedOrigins[1] != "https://b.example" {
+		t.Errorf("AllowedOrigins = %v, want [https://a.example https://b.example]", cfg.AllowedOrigins)
+	}
+}
+
+func TestLoadInvalidEnv(t *testing.T) {
+	t.Setenv("MESSENGER_ENV", "nope")
+
+	if _, err := Load(); err == nil {
+		t.Fatal("Load() error = nil, want validation error")
+	}
+}