Fix clippy warning

packages/hurl/src/http/client.rs

@@ -453,7 +453,7 @@ impl Client {
         }
 
         let response_code = self.handle.response_code().unwrap();
-        if response_code < 300 || response_code >= 400 {
+        if !(300..400).contains(&response_code) {
             return None;
         }
 

packages/hurl/src/main.rs

@@ -74,7 +74,7 @@ fn execute(
         .split(&contents)
         .map(|l| l.to_string())
         .collect();
-    let optional_filename = if filename == "" {
+    let optional_filename = if filename.is_empty() {
         None
     } else {
         Some(filename.to_string())

packages/hurl_core/src/parser/base64.rs

@@ -40,7 +40,7 @@ pub fn parse(reader: &mut Reader) -> Vec<u8> {
     let mut buf = vec![]; // base64 text
     loop {
         let pad = padding(reader);
-        if pad != "" {
+        if !pad.is_empty() {
             break;
         }
         let save = reader.state.clone();

packages/hurl_core/src/parser/expr.rs

@@ -59,7 +59,7 @@ pub fn parse2(reader: &mut Reader) -> ParseResult<'static, Expr> {
 fn variable_name(reader: &mut Reader) -> ParseResult<'static, Variable> {
     let start = reader.state.clone();
     let name = reader.read_while(|c| c.is_alphanumeric() || *c == '_');
-    if name == "" {
+    if name.is_empty() {
         return Err(Error {
             pos: start.pos,
             recoverable: false,

packages/hurlfmt/src/format/token.rs

@@ -760,7 +760,7 @@ impl Tokenizable for LineTerminator {
 impl Tokenizable for Whitespace {
     fn tokenize(&self) -> Vec<Token> {
         let mut tokens: Vec<Token> = vec![];
-        if self.value != "" {
+        if !self.value.is_empty() {
             tokens.push(Token::Whitespace(self.clone().value));
         }
         tokens

packages/hurlfmt/src/linter/rules.rs

@@ -685,7 +685,7 @@ impl Lintable<LineTerminator> for LineTerminator {
                 }
             }
             None => {
-                if self.space0.value != "" {
+                if !self.space0.value.is_empty() {
                     errors.push(Error {
                         source_info: self.clone().space0.source_info,
                         inner: LinterError::UnneccessarySpace {},
@@ -709,7 +709,7 @@ impl Lintable<LineTerminator> for LineTerminator {
             Some(comment) => Some(comment.lint()),
         };
         let newline = Whitespace {
-            value: if self.newline.value == "" {
+            value: if self.newline.value.is_empty() {
                 "".to_string()
             } else {
                 "\n".to_string()

packages/hurlfmt/src/main.rs

@@ -158,7 +158,7 @@ fn main() {
         .collect();
 
     let lines: Vec<String> = lines.iter().map(|s| (*s).to_string()).collect();
-    let optional_filename = if filename == "" {
+    let optional_filename = if filename.is_empty() {
         None
     } else {
         Some(filename.to_string())