imp(ibc-testkit): generalize Host for MockContext

.changelog/unreleased/improvements/1044-introduce-host-trait.md

@@ -0,0 +1,2 @@
+- [ibc-testkit] Refactor `HostBlock` enum to `Host` trait
+  ([\#1044](https://github.com/cosmos/ibc-rs/issues/1044))

ibc-testkit/src/fixtures/core/context.rs

@@ -8,19 +8,19 @@ use ibc::core::client::types::Height;
 use ibc::core::host::types::identifiers::ChainId;
 use ibc::core::primitives::prelude::*;
 use ibc::core::primitives::Timestamp;
-use tendermint_testgen::Validator as TestgenValidator;
 use typed_builder::TypedBuilder;
 
-use crate::hosts::block::{HostBlock, HostType};
+use crate::hosts::TestHost;
 use crate::testapp::ibc::core::types::{MockGenericContext, MockIbcStore, DEFAULT_BLOCK_TIME_SECS};
+use crate::utils::year_2023;
 
 /// Configuration of the `MockContext` type for generating dummy contexts.
 #[derive(Debug, TypedBuilder)]
 #[builder(build_method(into))]
-pub struct MockContextConfig {
-    #[builder(default = HostType::Mock)]
-    host_type: HostType,
-
+pub struct MockContextConfig<H>
+where
+    H: TestHost,
+{
     #[builder(default = ChainId::new("mockgaia-0").expect("Never fails"))]
     host_id: ChainId,
 
@@ -32,20 +32,21 @@ pub struct MockContextConfig {
     max_history_size: u64,
 
     #[builder(default, setter(strip_option))]
-    validator_set_history: Option<Vec<Vec<TestgenValidator>>>,
+    block_params_history: Option<Vec<H::BlockParams>>,
 
     #[builder(default = Height::new(0, 5).expect("Never fails"))]
     latest_height: Height,
 
-    #[builder(default = Timestamp::now())]
+    #[builder(default = year_2023())]
     latest_timestamp: Timestamp,
 }
 
-impl<S> From<MockContextConfig> for MockGenericContext<S>
+impl<S, H> From<MockContextConfig<H>> for MockGenericContext<S, H>
 where
     S: ProvableStore + Debug + Default,
+    H: TestHost,
 {
-    fn from(params: MockContextConfig) -> Self {
+    fn from(params: MockContextConfig<H>) -> Self {
         assert_ne!(
             params.max_history_size, 0,
             "The chain must have a non-zero max_history_size"
@@ -74,15 +75,15 @@ where
             .add(params.block_time)
             .expect("Never fails");
 
-        let history = if let Some(validator_set_history) = params.validator_set_history {
+        let host = H::with_chain_id(params.host_id);
+
+        let history = if let Some(validator_set_history) = params.block_params_history {
             (0..n)
                 .rev()
                 .map(|i| {
                     // generate blocks with timestamps -> N, N - BT, N - 2BT, ...
                     // where N = now(), BT = block_time
-                    HostBlock::generate_block_with_validators(
-                        params.host_id.clone(),
-                        params.host_type,
+                    host.generate_block(
                         params
                             .latest_height
                             .sub(i)
@@ -92,7 +93,6 @@ where
                             .sub(params.block_time * ((i + 1) as u32))
                             .expect("Never fails"),
                         &validator_set_history[(n - i) as usize - 1],
-                        &validator_set_history[(n - i) as usize],
                     )
                 })
                 .collect()
@@ -102,9 +102,7 @@ where
                 .map(|i| {
                     // generate blocks with timestamps -> N, N - BT, N - 2BT, ...
                     // where N = now(), BT = block_time
-                    HostBlock::generate_block(
-                        params.host_id.clone(),
-                        params.host_type,
+                    host.generate_block(
                         params
                             .latest_height
                             .sub(i)
@@ -113,14 +111,14 @@ where
                         next_block_timestamp
                             .sub(params.block_time * ((i + 1) as u32))
                             .expect("Never fails"),
+                        &H::BlockParams::default(),
                     )
                 })
                 .collect()
         };
 
         MockGenericContext {
-            host_chain_type: params.host_type,
-            host_chain_id: params.host_id.clone(),
+            host,
             max_history_size: params.max_history_size,
             history,
             block_time: params.block_time,

ibc-testkit/src/fixtures/mod.rs

@@ -6,6 +6,7 @@ use alloc::fmt::Debug;
 use ibc::core::handler::types::error::ContextError;
 use ibc::core::primitives::prelude::*;
 
+use crate::hosts::MockHost;
 use crate::testapp::ibc::core::types::MockContext;
 pub enum Expect {
     Success,
@@ -14,7 +15,7 @@ pub enum Expect {
 
 #[derive(Debug)]
 pub struct Fixture<M: Debug> {
-    pub ctx: MockContext,
+    pub ctx: MockContext<MockHost>,
     pub msg: M,
 }