diff --git a/src/tools/collections.rs b/src/tools/collections.rs
index 5f504e8..1bacac9 100644
--- a/src/tools/collections.rs
+++ b/src/tools/collections.rs
@@ -18,27 +18,22 @@ impl Tool for Transform {
     }
 
     fn run(&self, argument: &Value) -> Result<Value> {
-        let argument = self.check_type(argument)?;
+        let argument = self.check_type(argument)?.as_list()?;
+        let list = argument[0].as_list()?;
+        let function = argument[1].as_function()?;
+        let mut mapped_list = Vec::with_capacity(list.len());
 
-        if let Value::List(list) = argument {
-            let list = list[0].as_list()?;
-            let function = list[1].as_function()?;
-            let mut mapped_list = Vec::with_capacity(list.len());
+        for value in list {
+            let mut context = VariableMap::new();
 
-            for value in list {
-                let mut context = VariableMap::new();
+            context.set_value("input", value.clone())?;
 
-                context.set_value("input", value.clone())?;
+            let mapped_value = function.run_with_context(&mut context)?;
 
-                let mapped_value = function.run_with_context(&mut context)?;
-
-                mapped_list.push(mapped_value);
-            }
-
-            return Ok(Value::List(mapped_list));
+            mapped_list.push(mapped_value);
         }
 
-        self.fail(argument)
+        return Ok(Value::List(mapped_list));
     }
 }
 
@@ -84,7 +79,12 @@ impl Tool for Count {
             identifier: "count",
             description: "Return the number of items in a collection.",
             group: "collections",
-            inputs: vec![ValueType::Any],
+            inputs: vec![
+                ValueType::String,
+                ValueType::List,
+                ValueType::Map,
+                ValueType::Table,
+            ],
         }
     }
 
diff --git a/tests/collections.ds b/tests/collections.ds
index 936aaa3..4099e71 100644
--- a/tests/collections.ds
+++ b/tests/collections.ds
@@ -1,10 +1,11 @@
-
 # transform
+
 list = (1, 2, 3);
 test = transform(list, 'input + 1');
 assert_equal((2, 3, 4), test);
 
 # string
+
 test = string(42);
 assert_equal("42", test);
 
@@ -14,9 +15,100 @@ assert_equal("42.42", test);
 test = string(false);
 assert_equal("false", test);
 
+# create_table
+
+table = create_table(
+	("text", "num"),
+	(
+		("foo", 1),
+		("bar", 2)
+	)
+);
+
+# rows
+
+test = rows(table);
+assert_equal(
+	(
+		("foo", 1),
+		("bar", 2)
+	),
+	test
+);
+
+# insert
+
+test = insert(
+	table,
+	(
+		("foo", 1),
+		("bar", 2)
+	)
+);
+assert_equal(
+	create_table(
+		("text", "num"),
+		(
+			("foo", 1),
+			("bar", 2),
+			("foo", 1),
+			("bar", 2)
+		)
+	),
+	test
+);
+
+# select
+
+table = create_table(
+	("text", "number", "bool"),
+	(
+		("a", 1, true),
+		("b", 2, true),
+		("a", 3, true)
+	)
+);
+
+test_table = create_table(
+	("text", "bool"),
+	(
+		("a", true),
+		("b", true),
+		("a", true)
+	)
+);
+
+assert_equal(select(table, ("text", "bool")), test_table);
+
+test_table = create_table(
+	("text", "number", "bool"),
+	(
+		("a", 1, true),
+		("a", 3, true)
+	)
+);
+
+assert_equal(where(table, 'text == "a"'), test_table);
+
 # count
 
+table = create_table(
+	("text", "number", "bool"),
+	(
+		("a", 1, true),
+		("b", 2, true),
+		("a", 3, true)
+	)
+);
+test = count(table);
+assert_equal(3, test);
+
 test = count("123");
 assert_equal(3, test);
 
-# create_table
+test = count(1, 2, 3);
+assert_equal(3, test);
+
+map.x.z.y = 1;
+test = count(map);
+assert_equal(1, test);