improve abstractions for chain initialization and add README

Makefile

@@ -114,9 +114,9 @@ build-contract-tests-hooks:
 	mkdir -p $(BUILDDIR)
 	go build -mod=readonly $(BUILD_FLAGS) -o $(BUILDDIR)/ ./cmd/contract_tests
 
-build-e2e-upgrade:
+build-e2e-chain-init:
 	mkdir -p $(BUILDDIR)
-	go build -mod=readonly $(BUILD_FLAGS) -o $(BUILDDIR)/ ./tests/e2e/upgrade
+	go build -mod=readonly $(BUILD_FLAGS) -o $(BUILDDIR)/ ./tests/e2e/chain_init
 
 go-mod-cache: go.sum
 	@echo "--> Download go modules to local cache"
@@ -245,8 +245,8 @@ benchmark:
 docker-build-debug:
 	@docker build -t osmosis:debug --build-arg BASE_IMG_TAG=debug -f Dockerfile .
 
-docker-build-e2e-init:
-	@docker build -t osmosis-e2e:debug --build-arg BASE_IMG_TAG=debug -f tests/e2e//upgrade/init-e2e.Dockerfile .
+docker-build-e2e-chain-init:
+	@docker build -t osmosis-e2e-chain-init:debug -f tests/e2e/chain_init/chain-init.Dockerfile .
 
 ###############################################################################
 ###                                Linting                                  ###

tests/e2e/README.md

@@ -1,7 +1,15 @@
 # End-to-end Tests
 
-The package e2e defines an integration testing suite used for full end-to-end
-testing functionality.
+# Structure
+
+## `e2e` Package
+
+The `e2e` package defines an integration testing suite used for full end-to-end
+testing functionality. This package is decoupled from depending on the Osmosis codebase.
+It initializes the chains for testing via Docker files. As a result, the test suite may
+provide the desired Osmosis version to Docker containers during the initialization.
+This design allows for the opportunity for testing chain upgrades in the future by providing
+an older Osmosis version to the container, performing the chain upgrade, and running the latest test suite.
 
 The file e2e_suite_test.go defines the testing suite and contains the core
 bootstrapping logic that creates a testing environment via Docker containers.
@@ -11,3 +19,44 @@ The file e2e_test.go contains the actual end-to-end integration tests that
 utilize the testing suite.
 
 Currently, there is a single test in `e2e_test.go` to query the balances of a validator.
+
+## `chain` Package
+
+The `chain` package introduces the logic necessary for initializing a chain by creating a genesis
+file and all required configuration files such as the `app.tool. This package directly depends on the Osmosis codebase.
+
+## `upgrade` Package
+
+The `upgrade` package starts chain initialization. In addition, there is a Dockerfile `init-e2e.Dockerfile. 
+When executed, its container produces all files necessary for starting up a new chain. 
+These resulting files can be mounted on a volume and propagated to our production osmosis container to start the `osmosisd` service.
+
+The decoupling between chain initialization and start-up allows bringing our test suite as close to the production environment as possible.
+
+# Running Locally
+
+##### To build the binary that initializes the chain:
+
+```
+make build-e2e-chain-init
+```
+- The produced binary is an entrypoint to the `osmosis-e2e-chain-init:debug` image.
+
+##### To build the image for initializing the chain (`osmosis-e2e-chain-init:debug`):
+
+```
+make docker-build-e2e-chain-init
+```
+
+##### To run the chain initialization container locally:
+
+```
+docker run osmosis-e2e-chain-init:debug --data-dir=/tmp/osmo-test
+```
+- `--data-dir` flag is needed for outputting the files into a directory inside the container
+
+##### To build the debug Osmosis image:
+
+```
+make docker-build-e2e-debug
+```

tests/e2e/upgrade/init-e2e.Dockerfile → tests/e2e/chain_init/chain-init.Dockerfile

@@ -10,14 +10,14 @@ COPY . /osmosis
 # For more details see https://github.com/CosmWasm/wasmvm#builds-of-libwasmvm 
 ADD https://github.com/CosmWasm/wasmvm/releases/download/v1.0.0-beta7/libwasmvm_muslc.a /lib/libwasmvm_muslc.a
 RUN sha256sum /lib/libwasmvm_muslc.a | grep d0152067a5609bfdfb3f0d5d6c0f2760f79d5f2cd7fd8513cafa9932d22eb350
-RUN BUILD_TAGS=muslc make build-e2e-upgrade
+RUN BUILD_TAGS=muslc make build-e2e-chain-init
 
 ## Deploy image
 FROM ubuntu
 
-COPY --from=build /osmosis/build/upgrade /bin/upgrade
+COPY --from=build /osmosis/build/chain_init /bin/chain_init
 
 ENV HOME /osmosis
 WORKDIR $HOME
 
-ENTRYPOINT [ "upgrade" ]
+ENTRYPOINT [ "chain_init" ]

tests/e2e/upgrade/main.go → tests/e2e/chain_init/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	"github.com/osmosis-labs/osmosis/v7/tests/e2e/chain"
 )
@@ -17,12 +17,11 @@ func main() {
 		panic("data-dir is required")
 	}
 
-	tmpDir, err := ioutil.TempDir("", "osmosis-e2e-testnet-")
-	if err != nil {
+	if err := os.MkdirAll(dataDir, 0o755); err != nil {
 		panic(err)
 	}
 
-	chain, err := chain.Init(chain.ChainAID, tmpDir)
+	chain, err := chain.Init(chain.ChainAID, dataDir)
 	if err != nil {
 		panic(err)
 	}