Add the test suite

Similar to the one from v0.11. Has different csv loading logic and passes
context.

engine/libtest.go

@@ -26,8 +26,10 @@ import (
 	"os"
 	"os/exec"
 	"path"
+	"path/filepath"
 	"slices"
 	"strings"
+	"testing"
 	"time"
 
 	"github.com/cgrates/birpc"
@@ -317,3 +319,139 @@ func NewRPCClient(cfg *config.ListenCfg, encoding string) (*birpc.Client, error)
 		return nil, errors.New("invalid encoding")
 	}
 }
+
+// TestEnvironment holds the setup parameters and configurations
+// required for running integration tests.
+type TestEnvironment struct {
+	Name       string            // usually the name of the test
+	ConfigPath string            // file path to the main configuration file
+	ConfigJSON string            // contains the configuration JSON content if ConfigPath is missing
+	TpPath     string            // specifies the path to the tariff plans
+	TpFiles    map[string]string // maps CSV filenames to their content for tariff plan loading
+	LogBuffer  io.Writer         // captures the log output of the test environment
+	Encoding   string            // specifies the data encoding type (e.g., JSON, GOB)
+}
+
+// Setup initializes the testing environment using the provided configuration. It loads the configuration
+// from a specified path or creates a new one if the path is not provided. The method starts the engine,
+// establishes an RPC client connection, and loads CSV data if provided. It returns an RPC client and the
+// configuration.
+func (env TestEnvironment) Setup(t *testing.T, ctx *context.Context, engineDelay int) (*birpc.Client, *config.CGRConfig) {
+	t.Helper()
+
+	var cfg *config.CGRConfig
+	switch {
+	case env.ConfigPath != "":
+		var err error
+		cfg, err = config.NewCGRConfigFromPath(ctx, env.ConfigPath)
+		if err != nil {
+			t.Fatalf("failed to init config from path %s: %v", env.ConfigPath, err)
+		}
+	default:
+		cfg, env.ConfigPath = initCfg(t, ctx, env.ConfigJSON)
+	}
+
+	flushDBs(t, cfg, true, true)
+	startEngine(t, ctx, cfg, env.ConfigPath, engineDelay, env.LogBuffer)
+
+	client, err := NewRPCClient(cfg.ListenCfg(), env.Encoding)
+	if err != nil {
+		t.Fatalf("could not connect to cgr-engine: %v", err)
+	}
+
+	loadCSVs(t, env.TpPath, env.TpFiles)
+
+	return client, cfg
+}
+
+// initCfg creates a new CGRConfig from the provided configuration content string.
+// It generates a temporary directory and file path, writes the content to the configuration
+// file, and returns the created CGRConfig and the configuration directory path.
+func initCfg(t *testing.T, ctx *context.Context, cfgContent string) (cfg *config.CGRConfig, cfgPath string) {
+	t.Helper()
+	if cfgContent == utils.EmptyString {
+		t.Fatal("ConfigJSON is required but empty")
+	}
+	cfgPath = t.TempDir()
+	filePath := filepath.Join(cfgPath, "cgrates.json")
+	if err := os.WriteFile(filePath, []byte(cfgContent), 0644); err != nil {
+		t.Fatal(err)
+	}
+	cfg, err := config.NewCGRConfigFromPath(ctx, cfgPath)
+	if err != nil {
+		t.Fatalf("failed to init config from path %s: %v", cfgPath, err)
+	}
+	return cfg, cfgPath
+}
+
+// loadCSVs loads tariff plan data from CSV files. The CSV files are created based on the csvFiles map, where
+// the key represents the file name and the value the contains its contents. Assumes the data is loaded
+// automatically (RunDelay != 0)
+func loadCSVs(t *testing.T, tpPath string, csvFiles map[string]string) {
+
+	t.Helper()
+	if tpPath != "" {
+		for fileName, content := range csvFiles {
+			filePath := path.Join(tpPath, fileName)
+			if err := os.WriteFile(filePath, []byte(content), 0644); err != nil {
+				t.Fatalf("could not write to file %s: %v", filePath, err)
+			}
+		}
+	}
+}
+
+// flushDBs resets the databases specified in the configuration if the corresponding flags are true.
+func flushDBs(t *testing.T, cfg *config.CGRConfig, flushDataDB, flushStorDB bool) {
+	t.Helper()
+	if flushDataDB {
+		if err := InitDataDB(cfg); err != nil {
+			t.Fatalf("failed to flush %s dataDB: %v", cfg.DataDbCfg().Type, err)
+		}
+	}
+	if flushStorDB {
+		if err := InitStorDB(cfg); err != nil {
+			t.Fatalf("failed to flush %s storDB: %v", cfg.StorDbCfg().Type, err)
+		}
+	}
+}
+
+// startEngine starts the CGR engine process with the provided configuration. It writes engine logs to the provided
+// logBuffer (if any) and waits for the engine to be ready. If the passed context were to be cancelled, the engine
+// would also shut down.
+func startEngine(t *testing.T, ctx *context.Context, cfg *config.CGRConfig, cfgPath string, waitEngine int,
+	logBuffer io.Writer) {
+	t.Helper()
+	binPath, err := exec.LookPath("cgr-engine")
+	if err != nil {
+		t.Fatal("could not find cgr-engine executable")
+	}
+	engine := exec.CommandContext(
+		ctx,
+		binPath,
+		"-config_path", cfgPath,
+		"-logger", utils.MetaStdLog,
+	)
+	if logBuffer != nil {
+		engine.Stdout = logBuffer
+		engine.Stderr = logBuffer
+	}
+	if err := engine.Start(); err != nil {
+		t.Fatalf("cgr-engine command failed: %v", err)
+	}
+	t.Cleanup(func() {
+		if err := engine.Process.Kill(); err != nil {
+			t.Logf("failed to kill cgr-engine process (%d): %v", engine.Process.Pid, err)
+		}
+	})
+	fib := utils.FibDuration(time.Millisecond, 0)
+	for i := 0; i < 16; i++ {
+		time.Sleep(fib())
+		if _, err := jsonrpc.Dial(utils.TCP, cfg.ListenCfg().RPCJSONListen); err == nil {
+			break
+		}
+	}
+	if err != nil {
+		t.Fatalf("starting cgr-engine on port %s failed: %v", cfg.ListenCfg().RPCJSONListen, err)
+	}
+	time.Sleep(time.Duration(waitEngine) * time.Millisecond)
+}