unable to split small1.txt but even though it exist. cat small1.txt works though

split bug

/Users/Gerald/github/you-shell-fail/mytest>ls
a
a b.txt
abyss.txt
bar/
large1.txt
large2.txt
large3.txt
medium1.txt
medium2.txt
medium3.txt
small1.txt
small2.txt
small3.txt
split
/Users/Gerald/github/you-shell-fail/mytest>split small1.txt
/Users/Gerald/github/you-shell-fail/mytest>sg.edu.nus.comp.cs4218.exception.SplitException: split: small1.txt (No such file or directory)
	at sg.edu.nus.comp.cs4218.impl.app.SplitApplication.run(SplitApplication.java:51)
	at sg.edu.nus.comp.cs4218.impl.ShellImpl.runApp(ShellImpl.java:157)
	at sg.edu.nus.comp.cs4218.impl.cmd.CallCommand.evaluate(CallCommand.java:97)
	at sg.edu.nus.comp.cs4218.impl.cmd.PipeCommand.evaluate(PipeCommand.java:50)
	at sg.edu.nus.comp.cs4218.impl.ShellImpl.parseAndEvaluate(ShellImpl.java:323)
	at sg.edu.nus.comp.cs4218.impl.ShellImpl.main(ShellImpl.java:299)

cat small1.txt
/Users/Gerald/github/you-shell-fail/mytest>0
1
... (redacted)
674
/Users/Gerald/github/you-shell-fail/mytest>