Add equals() function

dsc_lib/src/functions/equals.rs

@@ -0,0 +1,74 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+use crate::DscError;
+use crate::configure::context::Context;
+use crate::functions::AcceptedArgKind;
+use super::Function;
+use serde_json::Value;
+
+#[derive(Debug, Default)]
+pub struct Equals {}
+
+impl Function for Equals {
+    fn accepted_arg_types(&self) -> Vec<AcceptedArgKind> {
+        vec![AcceptedArgKind::Number, AcceptedArgKind::String, AcceptedArgKind::Array, AcceptedArgKind::Object]
+    }
+
+    fn min_args(&self) -> usize {
+        2
+    }
+
+    fn max_args(&self) -> usize {
+        2
+    }
+
+    fn invoke(&self, args: &[Value], _context: &Context) -> Result<Value, DscError> {
+        Ok(Value::Bool(args[0] == args[1]))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::configure::context::Context;
+    use crate::parser::Statement;
+    use serde_json::Value;
+
+    #[test]
+    fn int_equal() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[equals(1,1)]", &Context::new()).unwrap();
+        assert_eq!(result, Value::Bool(true));
+    }
+
+    #[test]
+    fn int_notequal() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[equals(1,2]", &Context::new()).unwrap();
+        assert_eq!(result, Value::Bool(false));
+    }
+
+    #[test]
+    fn string_equal() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[equals('test','test')]", &Context::new()).unwrap();
+        assert_eq!(result, Value::Bool(true));
+    }
+
+    #[test]
+    fn string_notequal() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[equals('test','TEST')]", &Context::new()).unwrap();
+        assert_eq!(result, Value::Bool(false));
+    }
+
+    #[test]
+    fn different_types() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[equals(1,'string')]", &Context::new()).unwrap();
+        assert_eq!(result, Value::Bool(false));
+    }
+
+    // TODO: Add tests for arrays once `createArray()` is implemented
+    // TODO: Add tests for objects once `createObject()` is implemented
+}

dsc_lib/src/functions/mod.rs

@@ -14,6 +14,7 @@ pub mod concat;
 pub mod create_array;
 pub mod div;
 pub mod envvar;
+pub mod equals;
 pub mod int;
 pub mod max;
 pub mod min;
@@ -73,6 +74,7 @@ impl FunctionDispatcher {
         functions.insert("createArray".to_string(), Box::new(create_array::CreateArray{}));
         functions.insert("div".to_string(), Box::new(div::Div{}));
         functions.insert("envvar".to_string(), Box::new(envvar::Envvar{}));
+        functions.insert("equals".to_string(), Box::new(equals::Equals{}));
         functions.insert("int".to_string(), Box::new(int::Int{}));
         functions.insert("max".to_string(), Box::new(max::Max{}));
         functions.insert("min".to_string(), Box::new(min::Min{}));