It appeared it was going to let me do it, and failed while making the partition. Below is the details:
Running operation 1 of 3: Add “Test” by splitting “Macintosh HD”…
Resizing APFS Container designated by APFS Container Reference disk1
Verifying storage system
Using live mode.
Performing fsck_apfs -n -x -l /dev/disk0s2
Checking volume.
Checking the container superblock.
Checking the EFI jumpstart record.
Checking the space manager.
Checking the object map.
Checking the APFS volume superblock.
Checking the object map.
Checking the fsroot tree.
Checking the snapshot metadata tree.
Checking the extent ref tree.
Checking the snapshots.
Checking snapshot 1 of 12.
Checking snapshot 2 of 12.
Checking snapshot 3 of 12.
Checking snapshot 4 of 12.
Checking snapshot 5 of 12.
Checking snapshot 6 of 12.
Checking snapshot 7 of 12.
Checking snapshot 8 of 12.
Checking snapshot 9 of 12.
Checking snapshot 10 of 12.
Checking snapshot 11 of 12.
Checking snapshot 12 of 12.
Checking the APFS volume superblock.
Checking the object map.
Checking the fsroot tree.
Checking the snapshot metadata tree.
Checking the extent ref tree.
Checking the snapshots.
Checking the APFS volume superblock.
Checking the object map.
Checking the fsroot tree.
Checking the snapshot metadata tree.
Checking the extent ref tree.
Checking the snapshots.
Checking the APFS volume superblock.
Checking the object map.
Checking the fsroot tree.
Checking the snapshot metadata tree.
Checking the extent ref tree.
Checking the snapshots.
Verifying allocated space.
warning: Overallocation Detected on Main device: (24313205+1) bitmap address (18917695)
The volume /dev/disk0s2 appears to be OK.
Storage system check exit code is 0.
Shrinking APFS Physical Store disk0s2 from 250,790,436,864 to 248,745,791,488 bytes
Shrinking APFS data structures
Shrinking partition
Modifying partition map
Initialized /dev/rdisk0s3 as a 2 GB case-insensitive HFS Plus volume with a 8192k journal
Mounting disk
Creating a new empty APFS Container
Unmounting Volumes
Switching disk0s3 to APFS
Creating APFS Container
Created new APFS Container disk3
Preparing to add APFS Volume to APFS Container disk3
Creating APFS Volume
Created new APFS Volume disk3s1
Mounting APFS Volume
Setting volume permissions
Running operation 2 of 3: Erase “Test”…
Deleting APFS Container with all of its APFS Volumes
Unmounting Volumes
Unmounting Volume “Test” on disk3s1
Deleting Volumes
Deleting Container
Wiping former APFS disks
Switching content types
Reformatting former APFS disks
Initialized /dev/rdisk0s3 as a 2 GB case-insensitive HFS Plus volume with a 8192k journal
Mounting disk
Unmounting disk
Erasing
Volume name : Test
Partition offset : 486241264 sectors (248955527168 bytes)
Volume size : 3731304 sectors (1910427648 bytes)
Bytes per sector : 512
Bytes per cluster: 32768
FAT offset : 128 sectors (65536 bytes)
# FAT sectors : 512
Number of FATs : 1
Cluster offset : 640 sectors (327680 bytes)
# Clusters : 58291
Volume Serial # : 5a0dc6c1
Bitmap start : 2
Bitmap file size : 7287
Upcase start : 3
Upcase file size : 5836
Root start : 4
Mounting disk
Running operation 3 of 3: Erase “Test”…
Disk object invalid or unable to serialize.
Operation failed…