added exercises mapper test suite

internal/mappers/exercises_test.go

@@ -0,0 +1,28 @@
+package mappers
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/georgylobko/gym-log/internal/database"
+)
+
+func TestDatabaseExerciseToExercise(t *testing.T) {
+	dbExercise := database.GetExircisesRow{
+		ID:           1,
+		Name:         "Bench press",
+		PhotoUrl:     "http://im.com/benchpress",
+		MuscleGroups: []string{"Chest"},
+	}
+
+	exercise := ExerciseRow{
+		ID:           dbExercise.ID,
+		Name:         dbExercise.Name,
+		PhotoUrl:     dbExercise.PhotoUrl,
+		MuscleGroups: dbExercise.MuscleGroups,
+	}
+
+	if !reflect.DeepEqual(DatabaseExerciseRowToExercise(dbExercise), exercise) {
+		t.Fatalf("db exercise does not equal exercise after mapping")
+	}
+}