Added demo module to show explicit imports of macros (#1770)

* added demo module to node template

* updated comments

* replaced demo with updated template module

* Personal preferences here

* fixed comment inside macro

substrate/node-template/runtime/src/template.rs

@@ -0,0 +1,124 @@
+/// A runtime module template with necessary imports
+
+/// Feel free to remove or edit this file as needed.
+/// If you change the name of this file, make sure to update its references in runtime/src/lib.rs
+/// If you remove this file, you can remove those references
+
+
+/// For more guidance on Substrate modules, see the example module
+/// https://github.com/paritytech/substrate/blob/gav-template/srml/example/src/lib.rs
+
+use support::{decl_module, decl_storage, decl_event, StorageValue, dispatch::Result};
+use system::ensure_signed;
+
+/// The module's configuration trait.
+pub trait Trait: system::Trait {
+	// TODO: Add other types and constants required configure this module.
+
+	/// The overarching event type.
+	type Event: From<Event<Self>> + Into<<Self as system::Trait>::Event>;
+}
+
+/// This module's storage items.
+decl_storage! {
+	trait Store for Module<T: Trait> as TemplateModule {
+		// Just a dummy storage item. 
+		// Here we are declaring a StorageValue, `Something` as a Option<u32>
+		// `get(something)` is the default getter which returns either the stored `u32` or `None` if nothing stored
+		Something get(something): Option<u32>;
+	}
+}
+
+decl_module! {
+	/// The module declaration.
+	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
+		// Initializing events
+		// this is needed only if you are using events in your module
+		fn deposit_event<T>() = default;
+
+		// Just a dummy entry point.
+		// function that can be called by the external world as an extrinsics call
+		// takes a parameter of the type `AccountId`, stores it and emits an event
+		pub fn do_something(origin, something: u32) -> Result {
+			// TODO: You only need this if you want to check it was signed.
+			let who = ensure_signed(origin)?;
+
+			// TODO: Code to execute when something calls this.
+			// For example: the following line stores the passed in u32 in the storage
+			<Something<T>>::put(something);
+
+			// here we are raising the Something event
+			Self::deposit_event(RawEvent::SomethingStored(something, who));
+			Ok(())
+		}
+	}
+}
+
+decl_event!(
+	/// An event in this module.
+	pub enum Event<T> where AccountId = <T as system::Trait>::AccountId {
+		// Just a dummy event.
+		// Event `Something` is declared with a parameter of the type `u32` and `AccountId`
+		// To emit this event, we call the deposit funtion, from our runtime funtions
+		SomethingStored(u32, AccountId),
+	}
+);
+
+/// tests for this module
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	use runtime_io::with_externalities;
+	use primitives::{H256, Blake2Hasher};
+	use support::{impl_outer_origin, assert_ok};
+	use runtime_primitives::{
+		BuildStorage,
+		traits::{BlakeTwo256, IdentityLookup},
+		testing::{Digest, DigestItem, Header}
+	};
+
+	impl_outer_origin! {
+		pub enum Origin for Test {}
+	}
+
+	// For testing the module, we construct most of a mock runtime. This means
+	// first constructing a configuration type (`Test`) which `impl`s each of the
+	// configuration traits of modules we want to use.
+	#[derive(Clone, Eq, PartialEq)]
+	pub struct Test;
+	impl system::Trait for Test {
+		type Origin = Origin;
+		type Index = u64;
+		type BlockNumber = u64;
+		type Hash = H256;
+		type Hashing = BlakeTwo256;
+		type Digest = Digest;
+		type AccountId = u64;
+		type Lookup = IdentityLookup<u64>;
+		type Header = Header;
+		type Event = ();
+		type Log = DigestItem;
+	}
+	impl Trait for Test {
+		type Event = ();
+	}
+	type TemplateModule = Module<Test>;
+
+	// This function basically just builds a genesis storage key/value store according to
+	// our desired mockup.
+	fn new_test_ext() -> runtime_io::TestExternalities<Blake2Hasher> {
+		system::GenesisConfig::<Test>::default().build_storage().unwrap().0.into()
+	}
+
+	#[test]
+	fn it_works_for_default_value() {
+		with_externalities(&mut new_test_ext(), || {
+			// Just a dummy test for the dummy funtion `do_something`
+			// calling the `do_something` function with a value 42
+			assert_ok!(TemplateModule::do_something(Origin::signed(1), 42));
+			// asserting that the stored value is equal to what we stored
+			assert_eq!(TemplateModule::something(), Some(42));
+		});
+	}
+}