diff --git a/crates/codegen/src/expr.rs b/crates/codegen/src/expr.rs
index 8cdbaca..fbfdfe8 100644
--- a/crates/codegen/src/expr.rs
+++ b/crates/codegen/src/expr.rs
@@ -48,24 +48,6 @@ impl GenRust for Literal {
 
                 cg.add(")");
             }
-
-            Self::Array(values) => {
-                cg.add("[");
-
-                for val in values {
-                    val.gen_rust(ctx, cg);
-                }
-
-                cg.add("]");
-            }
-
-            Self::ArrayRepeat(value, repeat) => {
-                cg.add("[");
-                value.gen_rust(ctx, cg);
-                cg.add("; ");
-                repeat.gen_rust(ctx, cg);
-                cg.add("]");
-            }
         }
     }
 }
@@ -84,6 +66,26 @@ impl GenRust for Expression {
             Expression::Path(path) => cg.add(&path.get_rust()),
             Expression::Literal(literal) => literal.gen_rust(ctx, cg),
             Expression::Statement(stmt) => stmt.gen_rust(ctx, cg),
+            Expression::Array(values) => {
+                cg.add("[");
+
+                for (i, val) in values.iter().enumerate() {
+                    if i > 0 {
+                        cg.add(", ");
+                    }
+
+                    val.gen_rust(ctx, cg);
+                }
+
+                cg.add("]");
+            }
+            Expression::ArrayRepeat(value, repeat) => {
+                cg.add("[");
+                value.gen_rust(ctx, cg);
+                cg.add("; ");
+                repeat.gen_rust(ctx, cg);
+                cg.add("]");
+            }
             Expression::Fix {
                 initial,
                 prefixes,
@@ -101,6 +103,32 @@ impl GenRust for Expression {
                 cg.add(op);
                 rhs.gen_rust(ctx, cg);
             }
+
+            Expression::Closure {
+                return_type,
+                params,
+                body,
+            } => {
+                cg.add("|");
+                for (i, arg) in params.iter().enumerate() {
+                    if i > 0 {
+                        cg.add(", ");
+                    }
+
+                    arg.gen_rust(ctx, cg);
+                }
+                cg.add("| ");
+
+                if let Some(ty) = return_type {
+                    cg.add("-> ");
+                    cg.add(&ty.get_rust());
+                    cg.add(" ");
+
+                    cg.ensure_brackets_expr(ctx, body);
+                } else {
+                    body.gen_rust(ctx, cg);
+                }
+            }
         }
 
         if ensure_semicolon {
@@ -114,30 +142,13 @@ impl GenRust for Expression {
 }
 
 impl GenRust for Prefix {
-    fn gen_rust(&self, ctx: &mut Context, cg: &mut RustCodegen) {
+    fn gen_rust(&self, _ctx: &mut Context, cg: &mut RustCodegen) {
         match self {
             Self::Deref => cg.add("*"),
             Self::Ref => cg.add("&"),
             Self::RefMut => cg.add("&mut "),
             Self::Not => cg.add("!"),
             Self::Neg => cg.add("-"),
-            Self::Closure(ty, args) => {
-                cg.add("|");
-                for (i, arg) in args.iter().enumerate() {
-                    if i > 0 {
-                        cg.add(", ");
-                    }
-
-                    arg.gen_rust(ctx, cg);
-                }
-                cg.add("| ");
-
-                if let Some(ty) = ty {
-                    cg.add("-> ");
-                    cg.add(&ty.get_rust());
-                    cg.add(" ");
-                }
-            }
         }
     }
 }
diff --git a/crates/parser/src/ast/expr.rs b/crates/parser/src/ast/expr.rs
index 969cf21..04715c6 100644
--- a/crates/parser/src/ast/expr.rs
+++ b/crates/parser/src/ast/expr.rs
@@ -7,6 +7,13 @@ pub enum Expression {
     Literal(Literal),
     Path(ExprPath),
     Statement(Box<Statement>),
+    Array(Vec<Expression>),
+    ArrayRepeat(Box<Expression>, Box<Expression>),
+    Closure {
+        return_type: Option<TypeExpr>,
+        params: Vec<VarDecl>,
+        body: Box<Expression>,
+    },
     Fix {
         initial: Box<Expression>,
         prefixes: Vec<Prefix>,
@@ -26,8 +33,6 @@ pub enum Literal {
     Float(f64),
     Bool(bool),
     Tuple(Vec<Expression>),
-    Array(Vec<Expression>),
-    ArrayRepeat(Box<Expression>, Box<Expression>),
 }
 
 #[derive(Debug, Clone, Serialize)]
@@ -72,7 +77,6 @@ pub enum Prefix {
     Deref,
     Not,
     Neg,
-    Closure(Option<TypeExpr>, Vec<VarDecl>),
 }
 
 #[derive(Debug, Clone, Serialize)]
diff --git a/crates/parser/src/grammar.pest b/crates/parser/src/grammar.pest
index e4f748d..7eba693 100644
--- a/crates/parser/src/grammar.pest
+++ b/crates/parser/src/grammar.pest
@@ -30,6 +30,7 @@ keyword = {
   | "false"
   | "dyn"
   | "loop"
+  | "fn"
 }
 
 identifier = @{
@@ -448,7 +449,7 @@ match_stmt = {
 // CLOSURES
 // ------------------------------------------------------
 
-closure = { type_expr? ~ "|" ~ param_list ~ "|" }
+closure = { type_expr? ~ "fn" ~ "(" ~ param_list ~ ")" ~ expr }
 
 // ------------------------------------------------------
 // TUPLES & ARRAYS
@@ -458,10 +459,12 @@ tuple = {
     "(" ~ (expr ~ ("," ~ expr)*)? ~ ","? ~ ")"
 }
 
-array = {
-    "[" ~ expr ~ ";" ~ expr ~ "]" // Repeat notation: [0; 10]
+array_repeat = {
+    "[" ~ expr ~ ";" ~ expr ~ "]"
+}
 
-  | "[" ~ (expr ~ ("," ~ expr)* ~ ","?)? ~ "]" // Standard elements initialization
+array = {
+    "[" ~ (expr ~ ("," ~ expr)* ~ ","?)? ~ "]"
 }
 
 // ------------------------------------------------------
@@ -490,10 +493,12 @@ expr_path = {
 
 primary = {
     control_flow
+  | closure
   | basic_stmt
   | literal
   | expr_path
   | tuple
+  | array_repeat
   | array
 }
 
@@ -571,8 +576,7 @@ not_px     = { "!" }
 neg_px     = { "-" }
 
 prefix = {
-    closure
-  | deref_px
+    deref_px
   | mut_ref_px
   | ref_px
   | not_px
@@ -586,6 +590,7 @@ prefix = {
 bin_op = {
     "+="
   | "-="
+  | "*="
   | "/="
   | "%="
   | "&="
@@ -623,3 +628,4 @@ bin_op = {
 expr = { term ~ (bin_op ~ term)* }
 
 term = { prefix* ~ primary ~ postfix* }
+
diff --git a/crates/parser/src/parser/common/expr.rs b/crates/parser/src/parser/common/expr.rs
index b3236d8..e105511 100644
--- a/crates/parser/src/parser/common/expr.rs
+++ b/crates/parser/src/parser/common/expr.rs
@@ -75,6 +75,27 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for Expression {
                 ))
             }
 
+            Rule::closure => {
+                ast_expr!(Expression::Closure {
+                    return_type: consume_rule(&mut inner, Rule::type_expr)
+                        .map(TypeExpr::try_from)
+                        .transpose(),
+                    params: collect_recovered(inner.next().unwrap().into_inner()),
+                    body: Expression::try_from(inner.next().unwrap()).map(Box::new),
+                })
+            }
+
+            Rule::array => {
+                ast_expr!(Expression::Array(collect_recovered(inner)))
+            }
+
+            Rule::array_repeat => {
+                ast_expr!(Expression::ArrayRepeat(
+                    Expression::try_from(inner.next().unwrap()).map(Box::new),
+                    Expression::try_from(inner.next().unwrap()).map(Box::new)
+                ))
+            }
+
             Rule::primary => pair.into_inner().next().unwrap().try_into(),
             Rule::static_path => ast_expr!(Expression::Path(pair.try_into())),
             Rule::literal => ast_expr!(Expression::Literal(pair.try_into())),
@@ -108,16 +129,6 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for Prefix {
             Rule::ref_px => Self::Ref,
             Rule::not_px => Self::Not,
             Rule::neg_px => Self::Neg,
-            Rule::closure => {
-                let mut inner = pair.into_inner();
-
-                return ast_expr!(Self::Closure(
-                    consume_rule(&mut inner, Rule::type_expr)
-                        .map(TypeExpr::try_from)
-                        .transpose(),
-                    collect_recovered(inner.next().unwrap().into_inner())
-                ));
-            }
 
             _ => return AstError::bug_unimplemented(pair),
         })
diff --git a/crates/parser/src/parser/common/mod.rs b/crates/parser/src/parser/common/mod.rs
index 6994f64..c1d8f58 100644
--- a/crates/parser/src/parser/common/mod.rs
+++ b/crates/parser/src/parser/common/mod.rs
@@ -76,7 +76,7 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for Pattern {
                         return Ok(None);
                     }
 
-                    let mut inner = dbg!(v).into_inner();
+                    let mut inner = v.into_inner();
                     Some(ast_expr!((
                         Identifier::try_from(inner.next().unwrap()),
                         inner
diff --git a/mist-test/src/common/decl_test.mist b/mist-test/src/common/decl_test.mist
new file mode 100644
index 0000000..8c67ab1
--- /dev/null
+++ b/mist-test/src/common/decl_test.mist
@@ -0,0 +1,81 @@
+pub void test_let_basic() {
+    let x = 42;
+    assert_eq!(x, 42);
+}
+
+pub void test_let_typed() {
+    i32 x = 42;
+    assert_eq!(x, 42);
+
+    str* s = "hello";
+    assert_eq!(s, "hello");
+
+    bool b = true;
+    assert_eq!(b, true);
+
+    f64 f = 3.14;
+    assert_eq!(f, 3.14);
+}
+
+pub void test_let_mut() {
+    let mut x = 42;
+    x = 100;
+    assert_eq!(x, 100);
+}
+
+pub void test_let_tuple_destructure() {
+    let [a, b] = (10, "hello");
+    assert_eq!(a, 10);
+    assert_eq!(b, "hello");
+}
+
+pub void test_let_nested_tuple() {
+    let [a, [b, c]] = (1, (2, 3));
+    assert_eq!(a, 1);
+    assert_eq!(b, 2);
+    assert_eq!(c, 3);
+}
+
+pub void test_let_pattern_irrefutable() {
+    let x = 5;
+    let [y, z] = (1, 2);
+    assert_eq!(x, 5);
+    assert_eq!(y, 1);
+    assert_eq!(z, 2);
+}
+
+pub void test_multiple_decls() {
+    let a = 1;
+    let b = 2;
+    let c = 3;
+    assert_eq!(a + b + c, 6);
+}
+
+pub void test_let_with_type_and_init() {
+    f64 x = 10.0;
+    assert_eq!(x, 10.0);
+}
+
+pub void test_string_literal() {
+    let s = "hello, world!";
+    assert_eq!(s.len(), 13);
+}
+
+pub void test_let_bool() {
+    let t = true;
+    let f = false;
+    assert_eq!(t, !f);
+}
+
+pub void run_tests() {
+    test_let_basic();
+    test_let_typed();
+    test_let_mut();
+    test_let_tuple_destructure();
+    test_let_nested_tuple();
+    test_let_pattern_irrefutable();
+    test_multiple_decls();
+    test_let_with_type_and_init();
+    test_string_literal();
+    test_let_bool();
+}
diff --git a/mist-test/src/common/expr_test.mist b/mist-test/src/common/expr_test.mist
new file mode 100644
index 0000000..1132fba
--- /dev/null
+++ b/mist-test/src/common/expr_test.mist
@@ -0,0 +1,152 @@
+use std::cmp;
+
+pub void test_literals() {
+    assert_eq!(42, 42);
+    assert_eq!(3.14, 3.14);
+    assert_eq!(true, true);
+    assert_eq!(false, false);
+    assert_eq!("hello", "hello");
+}
+
+pub void test_tuples() {
+    let t = (1, true, "three");
+    assert_eq!(t.0, 1);
+    assert_eq!(t.1, true);
+    assert_eq!(t.2, "three");
+}
+
+pub void test_arrays() {
+    let arr = [1, 2, 3];
+    assert_eq!(arr[0], 1);
+    assert_eq!(arr[1], 2);
+    assert_eq!(arr[2], 3);
+}
+
+pub void test_array_repeat() {
+    let arr = [0; 5];
+    assert_eq!(arr[0], 0);
+    assert_eq!(arr[4], 0);
+    assert_eq!(arr.len(), 5);
+}
+
+pub void test_binary_arith() {
+    assert_eq!(10 + 5, 15);
+    assert_eq!(10 - 5, 5);
+    assert_eq!(10 * 5, 50);
+    assert_eq!(10 / 5, 2);
+    assert_eq!(10 % 3, 1);
+}
+
+pub void test_binary_cmp() {
+    assert_eq!(5 < 10, true);
+    assert_eq!(10 <= 10, true);
+    assert_eq!(10 > 5, true);
+    assert_eq!(10 >= 10, true);
+    assert_eq!(5 == 5, true);
+    assert_eq!(5 != 10, true);
+}
+
+pub void test_binary_logic() {
+    assert_eq!(true && true, true);
+    assert_eq!(true && false, false);
+    assert_eq!(true || false, true);
+    assert_eq!(false || false, false);
+}
+
+pub void test_binary_bit() {
+    assert_eq!(5 & 3, 1);
+    assert_eq!(5 | 3, 7);
+    assert_eq!(5 ^ 3, 6);
+    assert_eq!(1 << 2, 4);
+    assert_eq!(4 >> 1, 2);
+}
+
+pub void test_prefix() {
+    let x = 42;
+    assert_eq!(-x, -42);
+    assert_eq!(!true, false);
+    assert_eq!(!false, true);
+}
+
+pub void test_ref_deref() {
+    let x = 42;
+    let r = &x;
+    assert_eq!(*r, 42);
+}
+
+pub void test_postfix_inc_dec() {
+    let mut x = 5;
+    x++;
+    assert_eq!(x, 6);
+    x--;
+    assert_eq!(x, 5);
+}
+
+pub void test_as_cast() {
+    let x = 42;
+    assert_eq!(x as f64, 42.0);
+}
+
+pub void test_closure() {
+    let add = fn(let a, let b) a + b;
+    assert_eq!(add(2, 3), 5);
+}
+
+pub void test_block_expr() {
+    let x = {
+        let y = 10;
+        y + 5
+    };
+    assert_eq!(x, 15);
+}
+
+pub void test_if_expr() {
+    let x = if (true) { 1 } else { 2 };
+    assert_eq!(x, 1);
+
+    let y = if (false) { 1 } else { 2 };
+    assert_eq!(y, 2);
+}
+
+pub void test_range_expr() {
+    let r = 0..5;
+    let mut count = 0;
+    for (i : r) {
+        count++;
+    }
+    assert_eq!(count, 5);
+}
+
+pub void test_binary_assign() {
+    let mut x = 10;
+    x += 5;
+    assert_eq!(x, 15);
+    x -= 3;
+    assert_eq!(x, 12);
+    x *= 2;
+    assert_eq!(x, 24);
+    x /= 4;
+    assert_eq!(x, 6);
+    x %= 4;
+    assert_eq!(x, 2);
+}
+
+pub void run_tests() {
+    test_literals();
+    test_tuples();
+    test_arrays();
+    test_array_repeat();
+    test_binary_arith();
+    test_binary_cmp();
+    test_binary_logic();
+    test_binary_bit();
+    test_prefix();
+    test_ref_deref();
+    test_postfix_inc_dec();
+    test_as_cast();
+    test_closure();
+    test_block_expr();
+    test_if_expr();
+    test_range_expr();
+    test_binary_assign();
+}
diff --git a/mist-test/src/common/statement_test.mist b/mist-test/src/common/statement_test.mist
new file mode 100644
index 0000000..1aab6fa
--- /dev/null
+++ b/mist-test/src/common/statement_test.mist
@@ -0,0 +1,165 @@
+pub void test_var_decl() {
+    let x = 42;
+    assert_eq!(x, 42);
+
+    i32 y = 10;
+    assert_eq!(y, 10);
+
+    str* name = "mist";
+    assert_eq!(name, "mist");
+}
+
+pub void test_var_decl_with_init() {
+    let mut x = 0;
+    x = 5;
+    assert_eq!(x, 5);
+}
+
+pub void test_if_statement() {
+    let mut x = 0;
+
+    if (true) {
+        x = 1;
+    }
+    assert_eq!(x, 1);
+
+    if (false) {
+        x = 2;
+    } else {
+        x = 3;
+    }
+    assert_eq!(x, 3);
+}
+
+pub void test_if_else_if() {
+    let mut x = 0;
+
+    if (x == 1) {
+        x = 10;
+    } else if (x == 0) {
+        x = 20;
+    } else {
+        x = 30;
+    }
+    assert_eq!(x, 20);
+}
+
+pub void test_while_loop() {
+    let mut count = 0;
+
+    while (count < 5) {
+        count++;
+    }
+    assert_eq!(count, 5);
+}
+
+pub void test_for_loop() {
+    let mut sum = 0;
+
+    for (i : 0..4) {
+        sum += i;
+    }
+    assert_eq!(sum, 6);
+}
+
+pub void test_loop_stmt() {
+    let mut count = 0;
+
+    loop {
+        count++;
+        if (count >= 3) {
+            break;
+        }
+    }
+    assert_eq!(count, 3);
+}
+
+pub void test_break_continue() {
+    let mut sum = 0;
+
+    for (i : 0..10) {
+        if (i % 2 == 0) {
+            continue;
+        }
+        if (i >= 7) {
+            break;
+        }
+        sum += i;
+    }
+    assert_eq!(sum, 1 + 3 + 5);
+}
+
+pub i32 test_return_from_fn() {
+    return 42;
+}
+
+pub void test_block_scope() {
+    let x = {
+        let inner = 10;
+        inner + 5
+    };
+    assert_eq!(x, 15);
+}
+
+pub void test_match_literal() {
+    let x = 2;
+    let mut result = 0;
+
+    match (x) {
+        1 => { result = 10; }
+        2 => { result = 20; }
+        3 => { result = 30; }
+        _ => panic!();
+    }
+    assert_eq!(result, 20);
+}
+
+pub void test_match_or_pattern() {
+    let x = 1;
+    let mut result = 0;
+
+    match (x) {
+        1 | 2 => { result = 100; }
+        3 => { result = 200; }
+        _ => panic!();
+    }
+    assert_eq!(result, 100);
+}
+
+pub void test_match_default() {
+    let x = 99;
+    let mut result = 0;
+
+    match (x) {
+        1 => { result = 10; }
+        y => { result = y; }
+    }
+    assert_eq!(result, 99);
+}
+
+pub void test_for_with_pattern_destructure() {
+    let pairs = [(1, "a"), (2, "b")];
+    let mut keys = 0;
+
+    for ([k, _] : pairs) {
+        keys += k;
+    }
+    assert_eq!(keys, 3);
+}
+
+pub void run_tests() {
+    test_var_decl();
+    test_var_decl_with_init();
+    test_if_statement();
+    test_if_else_if();
+    test_while_loop();
+    test_for_loop();
+    test_loop_stmt();
+    test_break_continue();
+    assert_eq!(test_return_from_fn(), 42);
+    test_block_scope();
+    test_match_literal();
+    test_match_or_pattern();
+    test_match_default();
+    test_for_with_pattern_destructure();
+}
diff --git a/mist-test/src/common/types_test.mist b/mist-test/src/common/types_test.mist
new file mode 100644
index 0000000..2fac144
--- /dev/null
+++ b/mist-test/src/common/types_test.mist
@@ -0,0 +1,63 @@
+pub void test_integer_type() {
+    i32 x = 42;
+    assert_eq!(x, 42);
+}
+
+pub void test_float_type() {
+    f64 x = 3.14;
+    assert_eq!(x, 3.14);
+}
+
+pub void test_bool_type() {
+    bool x = true;
+    assert_eq!(x, true);
+
+    bool y = false;
+    assert_eq!(y, false);
+}
+
+pub void test_string_type() {
+    str* s = "hello";
+    assert_eq!(s, "hello");
+}
+
+pub void test_tuple_type() {
+    [i32, str*] t = (42, "answer");
+    assert_eq!(t.0, 42);
+    assert_eq!(t.1, "answer");
+}
+
+pub void test_ref_type() {
+    i32 x = 42;
+    i32* r = &x;
+    assert_eq!(*r, 42);
+}
+
+pub void test_mut_ref_type() {
+    let mut x = 42;
+    i32 mut* r = &mut x;
+    *r = 100;
+    assert_eq!(x, 100);
+}
+
+pub void test_void_type() {}
+
+i32 add(i32 a, i32 b) {
+    a + b
+}
+
+pub void test_fn_return_type() {
+    assert_eq!(add(3, 4), 7);
+}
+
+pub void run_tests() {
+    test_integer_type();
+    test_float_type();
+    test_bool_type();
+    test_string_type();
+    test_tuple_type();
+    test_ref_type();
+    test_mut_ref_type();
+    test_void_type();
+    test_fn_return_type();
+}
diff --git a/mist-test/src/items/attribute_test.mist b/mist-test/src/items/attribute_test.mist
new file mode 100644
index 0000000..3dd06b2
--- /dev/null
+++ b/mist-test/src/items/attribute_test.mist
@@ -0,0 +1,21 @@
+#[derive(Debug)]
+pub struct Debuggable {
+    i32 value,
+}
+
+pub void test_derive_attribute() {
+    let d = Debuggable { value: 42 };
+    assert_eq!(d.value, 42);
+}
+
+#[allow(unused_variables)]
+pub void test_allow_attribute() {
+    let x = 42;
+    let y = "unused";
+    assert_eq!(x, 42);
+}
+
+pub void run_tests() {
+    test_derive_attribute();
+    test_allow_attribute();
+}
diff --git a/mist-test/src/items/class_test.mist b/mist-test/src/items/class_test.mist
new file mode 100644
index 0000000..90d6720
--- /dev/null
+++ b/mist-test/src/items/class_test.mist
@@ -0,0 +1,58 @@
+pub class Counter {
+    pub i32 count;
+
+    pub constructor(i32 start) {
+        self.count = start;
+    }
+
+    pub void increment(self mut*) {
+        self.count++;
+    }
+
+    pub i32 get(self*) {
+        self.count
+    }
+}
+
+pub void test_class_create() {
+    let c = Counter::new(0);
+    assert_eq!(c.get(), 0);
+}
+
+pub void test_class_method() {
+    let mut c = Counter::new(5);
+    c.increment();
+    assert_eq!(c.get(), 6);
+}
+
+pub void test_class_field_access() {
+    let c = Counter::new(42);
+    assert_eq!(c.count, 42);
+}
+
+class NamedCounter : Counter {
+    pub String name;
+
+    pub constructor(i32 start, String name) {
+        self._super = Counter::new(start);
+
+        self.name = name;
+    }
+
+    pub String get_name(self*) {
+        self.name.clone()
+    }
+}
+
+pub void test_class_inherit() {
+    let nc = NamedCounter::new(10, "test".to_string());
+    assert_eq!(nc.get_name(), "test");
+    assert_eq!(nc.count, 10);
+}
+
+pub void run_tests() {
+    test_class_create();
+    test_class_method();
+    test_class_field_access();
+    test_class_inherit();
+}
diff --git a/mist-test/src/items/enum_test.mist b/mist-test/src/items/enum_test.mist
new file mode 100644
index 0000000..d111175
--- /dev/null
+++ b/mist-test/src/items/enum_test.mist
@@ -0,0 +1,60 @@
+enum OptionInt {
+    None,
+    Some[i32],
+}
+
+pub void test_enum_named() {
+    let x = OptionInt::None;
+    match (x) {
+        OptionInt::None => { assert_eq!(1, 1); }
+        OptionInt::Some[_] => { assert_eq!(0, 1); }
+    }
+}
+
+pub void test_enum_tuple() {
+    let x = OptionInt::Some(42);
+    match (x) {
+        OptionInt::None => { assert_eq!(0, 1); }
+        OptionInt::Some[v] => { assert_eq!(v, 42); }
+    }
+}
+
+enum Shape {
+    Circle { i32 radius },
+    Rect { i32 w, i32 h },
+}
+
+pub void test_enum_struct() {
+    let c = Shape::Circle { radius: 5 };
+    match (c) {
+        Shape::Circle { radius } => { assert_eq!(radius, 5); }
+        Shape::Rect { .. } => { assert_eq!(0, 1); }
+    }
+
+    let r = Shape::Rect { w: 3, h: 4 };
+    match (r) {
+        Shape::Circle { .. } => { assert_eq!(0, 1); }
+        Shape::Rect { w, h } => { assert_eq!(w * h, 12); }
+    }
+}
+
+enum Color {
+    Red,
+    Green,
+    Blue,
+}
+
+pub void test_enum_eq() {
+    let c = Color::Red;
+    match (c) {
+        Color::Red => { assert_eq!(1, 1); }
+        _ => { assert_eq!(0, 1); }
+    }
+}
+
+pub void run_tests() {
+    test_enum_named();
+    test_enum_tuple();
+    test_enum_struct();
+    test_enum_eq();
+}
diff --git a/mist-test/src/items/function_test.mist b/mist-test/src/items/function_test.mist
new file mode 100644
index 0000000..0278874
--- /dev/null
+++ b/mist-test/src/items/function_test.mist
@@ -0,0 +1,64 @@
+void greet() {
+    let mut x = 1;
+    x++;
+}
+
+pub void test_basic_function() {
+    greet();
+}
+
+i32 add(i32 a, i32 b) {
+    a + b
+}
+
+pub void test_fn_params() {
+    assert_eq!(add(2, 3), 5);
+}
+
+pub i32 test_fn_return() {
+    42
+}
+
+pub i32 test_fn_early_return() {
+    return 100;
+    0
+}
+
+pub i32 test_fn_mut_param(i32 mut x) {
+    x = x + 10;
+    x
+}
+
+pub void test_method_call() {
+    str* s = "hello";
+    assert_eq!(s.len(), 5);
+    assert_eq!(s.to_uppercase(), "HELLO");
+}
+
+i32 triple(i32 x) {
+    add(x, add(x, x))
+}
+
+pub void test_nested_fn_calls() {
+    assert_eq!(triple(5), 15);
+}
+
+i32 factorial(i32 n) {
+    if (n <= 1) 1
+    else (n) * (factorial(n - 1))
+}
+
+pub void test_recursive_fn() {
+    assert_eq!(factorial(5), 120);
+}
+
+pub void run_tests() {
+    test_basic_function();
+    test_fn_params();
+    assert_eq!(test_fn_return(), 42);
+    assert_eq!(test_fn_early_return(), 100);
+    assert_eq!(test_fn_mut_param(5), 15);
+    test_method_call();
+    test_nested_fn_calls();
+    test_recursive_fn();
+}
diff --git a/mist-test/src/items/impl_test.mist b/mist-test/src/items/impl_test.mist
new file mode 100644
index 0000000..4032913
--- /dev/null
+++ b/mist-test/src/items/impl_test.mist
@@ -0,0 +1,54 @@
+struct Vector2 {
+    i32 x,
+    i32 y,
+}
+
+impl Vector2 {
+    pub i32 magnitude(self*) {
+        self.x * self.x + self.y * self.y
+    }
+}
+
+pub void test_inherent_impl() {
+    let v = Vector2 { x: 3, y: 4 };
+    assert_eq!(v.magnitude(), 25);
+}
+
+trait Display {
+    String display(self*);
+}
+
+impl Display for Vector2 {
+    String display(self*) {
+        format!("({}, {})", self.x, self.y)
+    }
+}
+
+pub void test_trait_impl_block() {
+    let v = Vector2 { x: 1, y: 2 };
+    let s = v.display();
+    assert_eq!(s.len() > 0, true);
+}
+
+impl Vector2 {
+    pub Vector2 add(self*, Vector2 other) {
+        Vector2 {
+            x: self.x + other.x,
+            y: self.y + other.y,
+        }
+    }
+}
+
+pub void test_multiple_impls() {
+    let a = Vector2 { x: 1, y: 2 };
+    let b = Vector2 { x: 3, y: 4 };
+    let c = a.add(b);
+    assert_eq!(c.x, 4);
+    assert_eq!(c.y, 6);
+}
+
+pub void run_tests() {
+    test_inherent_impl();
+    test_trait_impl_block();
+    test_multiple_impls();
+}
diff --git a/mist-test/src/items/struct_test.mist b/mist-test/src/items/struct_test.mist
new file mode 100644
index 0000000..53698da
--- /dev/null
+++ b/mist-test/src/items/struct_test.mist
@@ -0,0 +1,44 @@
+struct Point {
+    i32 x,
+    i32 y,
+}
+
+pub void test_struct_create_access() {
+    let p = Point { x: 10, y: 20 };
+    assert_eq!(p.x, 10);
+    assert_eq!(p.y, 20);
+}
+
+pub void test_struct_mut_field() {
+    let mut p = Point { x: 1, y: 2 };
+    p.x = 100;
+    assert_eq!(p.x, 100);
+}
+
+pub void test_struct_destructure() {
+    let p = Point { x: 3, y: 4 };
+    let Point { x, y } = p;
+    assert_eq!(x, 3);
+    assert_eq!(y, 4);
+}
+
+struct Line {
+    Point start,
+    Point end,
+}
+
+pub void test_struct_nested() {
+    let l = Line {
+        start: Point { x: 0, y: 0 },
+        end: Point { x: 5, y: 10 },
+    };
+    assert_eq!(l.start.x, 0);
+    assert_eq!(l.end.y, 10);
+}
+
+pub void run_tests() {
+    test_struct_create_access();
+    test_struct_mut_field();
+    test_struct_destructure();
+    test_struct_nested();
+}
diff --git a/mist-test/src/items/trait_test.mist b/mist-test/src/items/trait_test.mist
new file mode 100644
index 0000000..ba93611
--- /dev/null
+++ b/mist-test/src/items/trait_test.mist
@@ -0,0 +1,39 @@
+trait Speak {
+    String speak(self*);
+}
+
+struct Dog {
+    String name,
+}
+
+impl Speak for Dog {
+    String speak(self*) {
+        "woof".to_string()
+    }
+}
+
+pub void test_trait_impl() {
+    let d = Dog { name: "Rex".to_string() };
+    assert_eq!(d.speak(), "woof");
+}
+
+trait Greet : Speak {
+    String greet(self*);
+}
+
+impl Greet for Dog {
+    String greet(self*) {
+        "hello".to_string()
+    }
+}
+
+pub void test_trait_with_requirement() {
+    let d = Dog { name: "Buddy".to_string() };
+    assert_eq!(d.speak(), "woof");
+    assert_eq!(d.greet(), "hello");
+}
+
+pub void run_tests() {
+    test_trait_impl();
+    test_trait_with_requirement();
+}
diff --git a/mist-test/src/main.mist b/mist-test/src/main.mist
index 1a14ec9..6e8730e 100644
--- a/mist-test/src/main.mist
+++ b/mist-test/src/main.mist
@@ -1,3 +1,18 @@
 void main() {
-    test_package::hello();
+    println!("running common tests...");
+    common::expr_test::run_tests();
+    common::statement_test::run_tests();
+    common::decl_test::run_tests();
+    common::types_test::run_tests();
+
+    println!("running items tests...");
+    items::function_test::run_tests();
+    items::struct_test::run_tests();
+    items::enum_test::run_tests();
+    items::class_test::run_tests();
+    items::trait_test::run_tests();
+    items::impl_test::run_tests();
+    items::attribute_test::run_tests();
+
+    println!("\x1b[32m\nAll tests passed!\x1b[0m");
 }
diff --git a/mist-test/src/test_package.mist b/mist-test/src/test_package.mist
deleted file mode 100644
index c35a53e..0000000
--- a/mist-test/src/test_package.mist
+++ /dev/null
@@ -1,3 +0,0 @@
-pub void hello() {
-    println!("Hello")
-}
\ No newline at end of file