> For the complete documentation index, see [llms.txt](https://davidsietz.gitbook.io/daas-workshop/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://davidsietz.gitbook.io/daas-workshop/module-02/02-section-02.md).

# Section II - Creating a Library

The Rust package comes automatically setup with a unit test in the `src/lib.rs` file. You can build and test your package in one command.

```
ArchConfWorkshopUser:~/environment/rust-daas (master) $ cargo test
    Finished test [unoptimized + debuginfo] target(s) in 0.00s
     Running target/debug/deps/rust_daas-393ccbe957dd9f3a

running 1 test
test tests::it_works ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

   Doc-tests rust-daas

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
```

By default, the manifest file (`Cargo.toml`) has only the **\[package]** section which contains the meta data about the package. The **\[dependencies]** section is empty. Since we created this package as a library, the **\[lib]** section is "assumed" and the `src/lib.rs` file is the default location and file name of the library module.

We will overwrite the defaults by adding the following lines to the `Cargo.toml`file after the **\[package]** section.

```rust
[lib]
name = "myapp"
path = "src/lib.rs"
```

try to rerun the build and test and notice that the library name changed from **rust-daas** to **myapp**.

```
ArchConfWorkshopUser:~/environment/rust-daas (master) $ cargo test
   Compiling rust-daas v0.1.0 (/home/ec2-user/environment/rust-daas)
    Finished test [unoptimized + debuginfo] target(s) in 0.58s
     Running target/debug/deps/myapp-8ec378e59bc20e80

running 1 test
test tests::it_works ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

   Doc-tests myapp

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
```