Update test_main.py

nit: Replace a full-width space with a space.

tests/test_main.py

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-"""Tests the BudouX　CLI."""
+"""Tests the BudouX CLI."""
 
 import io
 import sys