37 lines
852 B
Rust
37 lines
852 B
Rust
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// TODO: Define a function named `lowercase` that converts all characters in a string to lowercase,
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// modifying the input in place.
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// Does it need to take a `&mut String`? Does a `&mut [str]` work? Why or why not?
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn empty() {
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let mut s = String::from("");
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lowercase(&mut s);
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assert_eq!(s, "");
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}
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#[test]
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fn one_char() {
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let mut s = String::from("A");
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lowercase(&mut s);
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assert_eq!(s, "a");
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}
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#[test]
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fn multiple_chars() {
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let mut s = String::from("Hello, World!");
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lowercase(&mut s);
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assert_eq!(s, "hello, world!");
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}
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#[test]
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fn mut_slice() {
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let mut s = "Hello, World!".to_string();
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lowercase(s.as_mut_str());
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assert_eq!(s, "hello, world!");
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}
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}
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