# Strange text output from running Julia tests

**URL:** <https://discourse.julialang.org/t/strange-text-output-from-running-julia-tests/122379>\
**Category:** New to Julia\
**Tags:** question\
**Created:** [November 7, 2024, 12:13pm UTC](https://discourse.julialang.org/t/strange-text-output-from-running-julia-tests/122379 "2024-11-07T12:13:45Z")\
**Posts on this page:** 1\
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**Author:** ![goerz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/goerz/32/3269_2.png) [@goerz](https://discourse.julialang.org/u/goerz)\
**Post date:** [November 7, 2024, 3:26pm UTC](https://discourse.julialang.org/t/strange-text-output-from-running-julia-tests/122379/7 "2024-11-07T15:26:25Z")

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Generally, you’ll only need it after the outer testset. Or, if things are split over multiple files, potentially at the end of every file.

The point is that the REPL prints the result of any top-level expression it evaluates. If that expression is an `include`, and you don’t want the result of the last expression in the included file to be printed, you can make that last expression in the file be `nothing`.

This really goes back to your earlier confusion

> [@Why does append!(df1, df2) return a DataFrame, as well as modify the argument df1?](https://discourse.julialang.org/t/why-does-append-df1-df2-return-a-dataframe-as-well-as-modify-the-argument-df1/122329/3):
>
> Functions usually either modify one of their arguments, or do not modify their arguments and return a new value.

which is just completely false in Julia. All expressions in Julia (including `include`) return something. Moreover, the convention is for things to return the last expression from their “body”. There does not need to be an explicit `return` statement, and things return `nothing` only if they _explicitly_ return `nothing` (or the last expression they contain returns `nothing`).

In this case putting `nothing` at the end of the file make that the last expression in the “body” of the `include`, and thus causes `include` to return `nothing`, and nothing to be printed in the REPL.

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