Format assert statement (#5168)

crates/ruff_python_formatter/src/statement/stmt_assert.rs

@@ -1,4 +1,7 @@
-use crate::{not_yet_implemented, FormatNodeRule, PyFormatter};
+use crate::expression::maybe_parenthesize_expression;
+use crate::expression::parentheses::Parenthesize;
+use crate::{FormatNodeRule, PyFormatter};
+use ruff_formatter::prelude::{space, text};
 use ruff_formatter::{write, Buffer, FormatResult};
 use rustpython_parser::ast::StmtAssert;
 
@@ -7,6 +10,32 @@ pub struct FormatStmtAssert;
 
 impl FormatNodeRule<StmtAssert> for FormatStmtAssert {
     fn fmt_fields(&self, item: &StmtAssert, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(f, [not_yet_implemented(item)])
+        let StmtAssert {
+            range: _,
+            test,
+            msg,
+        } = item;
+
+        write!(
+            f,
+            [
+                text("assert"),
+                space(),
+                maybe_parenthesize_expression(test, item, Parenthesize::IfBreaks)
+            ]
+        )?;
+
+        if let Some(msg) = msg {
+            write!(
+                f,
+                [
+                    text(","),
+                    space(),
+                    maybe_parenthesize_expression(msg, item, Parenthesize::IfBreaks),
+                ]
+            )?;
+        }
+
+        Ok(())
     }
 }