Add tests & Service's Configuration has optional fields that shouldn't be optional (#4842)

Related to #4776 
Related to https://github.com/paritytech/polkadot/pull/832

To summarize the changes:
1. I did not manage to validate with types the service's Configuration. But I did reduce the possibility of errors by moving all the "fill" functions to their respective structopts
2. I split params.rs to multiple modules: one module params for just CLI parameters and one module commands for CLI subcommands (and RunCmd). Every command and params are in their own file so things are grouped better together and easier to remove
3. I removed the run and run_subcommand helpers as they are not helping much anymore. Running a command is always a set of 3 commands: 1. init 2. update config 3. run. This still allow the user to change the config before arguments get parsed or right after.
4. I added tests for all subcommands.
5. [deleted]

Overall the aim is to improve the situation with the Configuration and the optional parameters, add tests, make the API more consistent and simpler.

substrate/bin/node/inspect/src/command.rs

@@ -0,0 +1,204 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Command ran by the CLI
+
+use std::{
+	fmt::Debug,
+	str::FromStr,
+};
+
+use crate::cli::{InspectCmd, InspectSubCmd};
+use crate::{Inspector, PrettyPrinter};
+
+impl InspectCmd {
+	/// Initialize
+	pub fn init(&self, version: &sc_cli::VersionInfo) -> sc_cli::Result<()> {
+		self.shared_params.init(version)
+	}
+
+	/// Parse CLI arguments and initialize given config.
+	pub fn update_config<G, E>(
+		&self,
+		mut config: &mut sc_service::config::Configuration<G, E>,
+		spec_factory: impl FnOnce(&str) -> Result<Option<sc_service::ChainSpec<G, E>>, String>,
+		version: &sc_cli::VersionInfo,
+	) -> sc_cli::Result<()> where
+		G: sc_service::RuntimeGenesis,
+		E: sc_service::ChainSpecExtension,
+	{
+		self.shared_params.update_config(config, spec_factory, version)?;
+
+		// make sure to configure keystore
+		config.use_in_memory_keystore()?;
+
+		// and all import params (especially pruning that has to match db meta)
+		self.import_params.update_config(
+			&mut config,
+			sc_service::Roles::FULL,
+			self.shared_params.dev,
+		)?;
+
+		Ok(())
+	}
+
+	/// Run the inspect command, passing the inspector.
+	pub fn run<B, P>(
+		self,
+		inspect: Inspector<B, P>,
+	) -> sc_cli::Result<()> where
+		B: sp_runtime::traits::Block,
+		B::Hash: FromStr,
+		P: PrettyPrinter<B>,
+	{
+		match self.command {
+			InspectSubCmd::Block { input } => {
+				let input = input.parse()?;
+				let res = inspect.block(input)
+					.map_err(|e| format!("{}", e))?;
+				println!("{}", res);
+				Ok(())
+			},
+			InspectSubCmd::Extrinsic { input } => {
+				let input = input.parse()?;
+				let res = inspect.extrinsic(input)
+					.map_err(|e| format!("{}", e))?;
+				println!("{}", res);
+				Ok(())
+			},
+		}
+	}
+}
+
+/// A block to retrieve.
+#[derive(Debug, Clone, PartialEq)]
+pub enum BlockAddress<Hash, Number> {
+	/// Get block by hash.
+	Hash(Hash),
+	/// Get block by number.
+	Number(Number),
+	/// Raw SCALE-encoded bytes.
+	Bytes(Vec<u8>),
+}
+
+impl<Hash: FromStr, Number: FromStr> FromStr for BlockAddress<Hash, Number> {
+	type Err = String;
+
+	fn from_str(s: &str) -> Result<Self, Self::Err> {
+		// try to parse hash first
+		if let Ok(hash) = s.parse() {
+			return Ok(Self::Hash(hash))
+		}
+
+		// then number
+		if let Ok(number) = s.parse() {
+			return Ok(Self::Number(number))
+		}
+
+		// then assume it's bytes (hex-encoded)
+		sp_core::bytes::from_hex(s)
+			.map(Self::Bytes)
+			.map_err(|e| format!(
+				"Given string does not look like hash or number. It could not be parsed as bytes either: {}",
+				e
+			))
+	}
+}
+
+/// An extrinsic address to decode and print out.
+#[derive(Debug, Clone, PartialEq)]
+pub enum ExtrinsicAddress<Hash, Number> {
+	/// Extrinsic as part of existing block.
+	Block(BlockAddress<Hash, Number>, usize),
+	/// Raw SCALE-encoded extrinsic bytes.
+	Bytes(Vec<u8>),
+}
+
+impl<Hash: FromStr + Debug, Number: FromStr + Debug> FromStr for ExtrinsicAddress<Hash, Number> {
+	type Err = String;
+
+	fn from_str(s: &str) -> Result<Self, Self::Err> {
+		// first try raw bytes
+		if let Ok(bytes) = sp_core::bytes::from_hex(s).map(Self::Bytes) {
+			return Ok(bytes)
+		}
+
+		// split by a bunch of different characters
+		let mut it = s.split(|c| c == '.' || c == ':' || c == ' ');
+		let block = it.next()
+			.expect("First element of split iterator is never empty; qed")
+			.parse()?;
+
+		let index = it.next()
+			.ok_or_else(|| format!("Extrinsic index missing: example \"5:0\""))?
+			.parse()
+			.map_err(|e| format!("Invalid index format: {}", e))?;
+
+		Ok(Self::Block(block, index))
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use sp_core::hash::H160 as Hash;
+
+	#[test]
+	fn should_parse_block_strings() {
+		type BlockAddress = super::BlockAddress<Hash, u64>;
+
+		let b0 = BlockAddress::from_str("3BfC20f0B9aFcAcE800D73D2191166FF16540258");
+		let b1 = BlockAddress::from_str("1234");
+		let b2 = BlockAddress::from_str("0");
+		let b3 = BlockAddress::from_str("0x0012345f");
+
+
+		assert_eq!(b0, Ok(BlockAddress::Hash(
+			"3BfC20f0B9aFcAcE800D73D2191166FF16540258".parse().unwrap()
+		)));
+		assert_eq!(b1, Ok(BlockAddress::Number(1234)));
+		assert_eq!(b2, Ok(BlockAddress::Number(0)));
+		assert_eq!(b3, Ok(BlockAddress::Bytes(vec![0, 0x12, 0x34, 0x5f])));
+	}
+
+	#[test]
+	fn should_parse_extrinsic_address() {
+		type BlockAddress = super::BlockAddress<Hash, u64>;
+		type ExtrinsicAddress = super::ExtrinsicAddress<Hash, u64>;
+
+		let e0 = ExtrinsicAddress::from_str("1234");
+		let b0 = ExtrinsicAddress::from_str("3BfC20f0B9aFcAcE800D73D2191166FF16540258:5");
+		let b1 = ExtrinsicAddress::from_str("1234:0");
+		let b2 = ExtrinsicAddress::from_str("0 0");
+		let b3 = ExtrinsicAddress::from_str("0x0012345f");
+
+
+		assert_eq!(e0, Err("Extrinsic index missing: example \"5:0\"".into()));
+		assert_eq!(b0, Ok(ExtrinsicAddress::Block(
+			BlockAddress::Hash("3BfC20f0B9aFcAcE800D73D2191166FF16540258".parse().unwrap()),
+			5
+		)));
+		assert_eq!(b1, Ok(ExtrinsicAddress::Block(
+			BlockAddress::Number(1234),
+			0
+		)));
+		assert_eq!(b2, Ok(ExtrinsicAddress::Block(
+			BlockAddress::Number(0),
+			0
+		)));
+		assert_eq!(b3, Ok(ExtrinsicAddress::Bytes(vec![0, 0x12, 0x34, 0x5f])));
+	}
+}