Add subject and test of exercise `strings`

rust/tests/strings_test/Cargo.lock

@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "strings"
+version = "0.1.0"
+
+[[package]]
+name = "strings_test"
+version = "0.1.0"
+dependencies = [
+ "strings",
+]

rust/tests/strings_test/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "strings_test"
+version = "0.1.0"
+authors = ["Augusto <aug.ornelas@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+strings = { path = "../../../../rust-piscine-solutions/strings"}

rust/tests/strings_test/src/main.rs

@@ -0,0 +1,39 @@
+// Write a function that receives a string slice and returns the
+// length of character of the string
+
+use strings::*;
+
+fn main() {
+	println!("lenght of {} = {}", "❤", "❤".len());
+	println!("lenght of {} = {}", "❤", char_lenght("❤"));
+	println!("lenght of {} = {}", "形声字", char_lenght("形聲字"));
+	println!("lenght of {} = {}", "形声字", "形聲字".len());
+	println!("lenght of {} = {}", "change", "change".len());
+	println!("lenght of {} = {}", "change", char_lenght("change"));
+	println!("char lenght of {} = {}", "😍", char_lenght("😍"));
+}
+
+// fn char_lenght(s: &str) -> usize {
+// 	let mut chars = 0;
+// 	for _ in s.chars() {
+// 		chars += 1;
+// 	}
+// 	chars
+// }
+
+#[test]
+fn test_ascii() {
+	let s = "ascii";
+	assert_eq!(char_lenght(s), 5);
+}
+
+#[test]
+fn test_emoji() {
+	let s = "❤😍";
+	assert_eq!(char_lenght(s), 2);
+}
+#[test]
+fn test_chinese_char() {
+	let s = "形声字";
+	assert_eq!(char_lenght(s), 3);
+}

subjects/strings/README.md

@@ -0,0 +1,36 @@
+## strings
+
+### Instructions
+
+Write a function that receives a string slice and returns the number of character of the string
+
+### Expected Function
+
+```rust
+fn char_length(s: &str) -> usize {
+}
+```
+
+### Usage
+
+Here is a program to test your function.
+
+```rust
+fn main() {
+	println!("length of {} = {}", "❤", char_length("❤"));
+	println!("length of {} = {}", "形声字", char_length("形聲字"));
+	println!("length of {} = {}", "change", char_length("change"));
+	println!("length of {} = {}", "😍", char_length("😍"));
+}
+```
+
+And its output
+
+```console
+student@ubuntu:~/[[ROOT]]/test$ cargo run
+length of ❤ = 1
+length of 形声字 = 3
+length of change = 6
+length of 😍 = 1
+student@ubuntu:~/[[ROOT]]/test$
+```