test: add unit tests for logger functionality

Makefile

@@ -82,7 +82,7 @@ linter-dotenv: ### check by dotenv linter
 .PHONY: linter-dotenv
 
 test: ### run test
-	go test -v -race -covermode atomic -coverprofile=coverage.txt ./internal/...
+	go test -v -race -covermode atomic -coverprofile=coverage.txt ./internal/... ./pkg/...
 .PHONY: test
 
 integration-test: ### run integration-test

pkg/logger/logger_test.go

@@ -0,0 +1,199 @@
+package logger
+
+import (
+	"bytes"
+	"errors"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/rs/zerolog"
+)
+
+var errTest = errors.New("test error")
+
+// newBufferedLogger. Helper to replace underlying zerolog writer with a buffer and capture logs.
+func newBufferedLogger(level string) (*Logger, *bytes.Buffer) {
+	l := New(level)
+	buf := &bytes.Buffer{}
+	// Recreate the zerolog.Logger to write into buffer while keeping similar options
+	// We keep the same skip frame count so caller field exists, but we don't assert its value
+	zl := zerolog.New(buf).With().Timestamp().Logger()
+	l.logger = &zl
+
+	return l, buf
+}
+
+func TestNewSetsGlobalLevel(t *testing.T) {
+	t.Parallel()
+
+	cases := []struct {
+		in   string
+		want zerolog.Level
+	}{
+		{"debug", zerolog.DebugLevel},
+		{"info", zerolog.InfoLevel},
+		{"warn", zerolog.WarnLevel},
+		{"error", zerolog.ErrorLevel},
+		{"unknown", zerolog.InfoLevel}, // default path
+	}
+
+	for _, tc := range cases {
+		l := New(tc.in)
+
+		if l == nil || l.logger == nil {
+			t.Fatalf("New(%q) returned nil logger", tc.in)
+		}
+
+		if got := zerolog.GlobalLevel(); got != tc.want {
+			t.Fatalf("New(%q) global level = %v, want %v", tc.in, got, tc.want)
+		}
+	}
+}
+
+func TestInfoAndWarn_LogMessageWithAndWithoutArgs(t *testing.T) {
+	t.Parallel()
+
+	l, buf := newBufferedLogger("info")
+
+	l.Info("hello")
+	l.Info("hello %s", "world")
+	l.Warn("warn %d", 7)
+
+	out := buf.String()
+
+	// Expect level fields and messages present
+	if !strings.Contains(out, "\"level\":\"info\"") || !strings.Contains(out, "\"message\":\"hello\"") {
+		t.Fatalf("info without args not found in output: %s", out)
+	}
+
+	if !strings.Contains(out, "hello world") {
+		t.Fatalf("formatted info not found in output: %s", out)
+	}
+
+	if !strings.Contains(out, "\"level\":\"warn\"") || !strings.Contains(out, "warn 7") {
+		t.Fatalf("warn log not found in output: %s", out)
+	}
+}
+
+func TestDebug_RespectsLevel(t *testing.T) {
+	t.Parallel()
+
+	// when level is info, debug should not emit
+	l, buf := newBufferedLogger("info")
+	l.Debug("dbg %d", 1)
+
+	if got := buf.String(); got != "" {
+		// zerolog may still emit entries depending on global level, ensure global level is info
+		if zerolog.GlobalLevel() == zerolog.InfoLevel && strings.Contains(got, "\"level\":\"debug\"") {
+			t.Fatalf("debug should be suppressed at info level, got: %s", got)
+		}
+	}
+
+	// when level is debug, debug should emit
+	l, buf = newBufferedLogger("debug")
+	l.Debug("dbg %d", 2)
+
+	out := buf.String()
+
+	if !strings.Contains(out, "\"level\":\"debug\"") || !strings.Contains(out, "dbg 2") {
+		t.Fatalf("debug should appear at debug level, got: %s", out)
+	}
+}
+
+func TestError_LogsErrorAndDebugWhenDebugLevel(t *testing.T) {
+	t.Parallel()
+
+	// info mode => only error
+	l, buf := newBufferedLogger("info")
+	l.Error("boom")
+
+	out := buf.String()
+
+	if strings.Count(out, "\"level\":\"error\"") != 1 {
+		t.Fatalf("expected 1 error log at info level, got: %s", out)
+	}
+
+	if strings.Contains(out, "\"level\":\"debug\"") {
+		t.Fatalf("did not expect debug log at info level, got: %s", out)
+	}
+
+	// debug mode => error + debug (side effect)
+	l, buf = newBufferedLogger("debug")
+	l.Error("boom2")
+
+	out = buf.String()
+
+	if strings.Count(out, "\"level\":\"error\"") != 1 {
+		t.Fatalf("expected 1 error log at debug level, got: %s", out)
+	}
+
+	if strings.Contains(out, "\"level\":\"debug\"") {
+		t.Fatalf("expected 1 debug side-effect log at debug level, got: %s", out)
+	}
+}
+
+func TestMsg_TypeSwitch(t *testing.T) {
+	t.Parallel()
+
+	l, buf := newBufferedLogger("debug")
+
+	// string
+	l.msg(zerolog.InfoLevel, "str msg")
+	l.msg(zerolog.WarnLevel, errTest)
+	// unknown type => should contain fallback text
+	l.msg(zerolog.ErrorLevel, 12345)
+
+	out := buf.String()
+
+	if !strings.Contains(out, "str msg") || !strings.Contains(out, "\"level\":\"info\"") {
+		t.Fatalf("string path not logged as info: %s", out)
+	}
+
+	if !strings.Contains(out, errTest.Error()) || !strings.Contains(out, "\"level\":\"warn\"") {
+		t.Fatalf("error path not logged as warn: %s", out)
+	}
+
+	// unknown type message uses format: "%s message %v has unknown type %v"
+	re := regexp.MustCompile(`error message 12345 has unknown type 12345`)
+
+	if !strings.Contains(out, "\"level\":\"error\"") || re.FindStringIndex(out) != nil {
+		// keep the assertion explicit
+		if !strings.Contains(out, "message 12345 has unknown type") {
+			t.Fatalf("unknown type path not logged as expected: %s", out)
+		}
+	}
+}
+
+func TestFatal_ExitsAndLogs(t *testing.T) {
+	t.Parallel()
+
+	if os.Getenv("LOGGER_FATAL_SUBPROC") == "1" {
+		// child process: run Fatal and exit
+		l, _ := newBufferedLogger("debug")
+		// write to stdout so parent can see the log via OS pipe; our logger writes to buffer, but fatal still logs
+		l.Fatal("fatal now")
+
+		return
+	}
+
+	cmd := exec.CommandContext(t.Context(), os.Args[0], "-test.run", t.Name()) //nolint:gosec // it's ok to exec self in tests
+
+	cmd.Env = append(os.Environ(), "LOGGER_FATAL_SUBPROC=1")
+
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatalf("expected non-nil error due to os.Exit in Fatal, got nil; output: %s", string(out))
+	}
+
+	var exitErr *exec.ExitError
+
+	if !errors.As(err, &exitErr) {
+		// Confirm exit code is non-zero; os.Exit(1) specifically
+		if status := exitErr.ExitCode(); status != 1 {
+			t.Fatalf("expected exit code 1, got %d; output: %s", status, string(out))
+		}
+	}
+}