test: expand handler tests to 53.4% coverage

internal/service/habit_test.go

@@ -0,0 +1,41 @@
+package service
+
+import (
+	"database/sql"
+	"testing"
+	"time"
+
+	"github.com/daniil/homelab-api/internal/model"
+)
+
+func TestNewHabitService(t *testing.T) {
+	svc := NewHabitService(nil, nil)
+	if svc == nil {
+		t.Fatal("expected non-nil HabitService")
+	}
+}
+
+func TestErrFutureDate(t *testing.T) {
+	if ErrFutureDate.Error() != "cannot log habit for future date" {
+		t.Errorf("unexpected: %s", ErrFutureDate.Error())
+	}
+}
+
+func TestErrAlreadyLogged(t *testing.T) {
+	if ErrAlreadyLogged.Error() != "habit already logged for this date" {
+		t.Errorf("unexpected: %s", ErrAlreadyLogged.Error())
+	}
+}
+
+// When totalLogs==0 the function returns immediately without any DB access.
+func TestCalculateCompletionPctWithFreezes_ZeroLogs(t *testing.T) {
+	svc := &HabitService{}
+	habit := &model.Habit{
+		Frequency: "daily",
+		StartDate: sql.NullTime{Time: time.Now().AddDate(0, 0, -30), Valid: true},
+	}
+	pct := svc.calculateCompletionPctWithFreezes(habit, 0)
+	if pct != 0 {
+		t.Errorf("expected 0%% for zero logs, got %.2f", pct)
+	}
+}