cmd/evm: adds ability to run individual state test file (#14998)

* cmd/evm: adds ability to run individual state test file

* cmd/evm: Fix statetest runner to be more json friendly

* cmd/evm, tests: minor polishes, dump state on fail

2 files changed, 8 insertions, 7 deletions

diff --git a/tests/state_test.go b/tests/state_test.go
index 4b6ba8b31..1fb7f5908 100644
--- a/tests/state_test.go
+++ b/tests/state_test.go
@@ -50,7 +50,8 @@ func TestState(t *testing.T) {
 					t.Skip("constantinople not supported yet")
 				}
 				withTrace(t, test.gasLimit(subtest), func(vmconfig vm.Config) error {
-					return st.checkFailure(t, name, test.Run(subtest, vmconfig))
+					_, err := test.Run(subtest, vmconfig)
+					return st.checkFailure(t, name, err)
 				})
 			})
 		}
diff --git a/tests/state_test_util.go b/tests/state_test_util.go
index ecaa6c668..64bf09cb4 100644
--- a/tests/state_test_util.go
+++ b/tests/state_test_util.go
@@ -120,10 +120,10 @@ func (t *StateTest) Subtests() []StateSubtest {
 }
 
 // Run executes a specific subtest.
-func (t *StateTest) Run(subtest StateSubtest, vmconfig vm.Config) error {
+func (t *StateTest) Run(subtest StateSubtest, vmconfig vm.Config) (*state.StateDB, error) {
 	config, ok := Forks[subtest.Fork]
 	if !ok {
-		return UnsupportedForkError{subtest.Fork}
+		return nil, UnsupportedForkError{subtest.Fork}
 	}
 	block, _ := t.genesis(config).ToBlock()
 	db, _ := ethdb.NewMemDatabase()
@@ -132,7 +132,7 @@ func (t *StateTest) Run(subtest StateSubtest, vmconfig vm.Config) error {
 	post := t.json.Post[subtest.Fork][subtest.Index]
 	msg, err := t.json.Tx.toMessage(post)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	context := core.NewEVMContext(msg, block.Header(), nil, &t.json.Env.Coinbase)
 	context.GetHash = vmTestBlockHash
@@ -145,13 +145,13 @@ func (t *StateTest) Run(subtest StateSubtest, vmconfig vm.Config) error {
 		statedb.RevertToSnapshot(snapshot)
 	}
 	if logs := rlpHash(statedb.Logs()); logs != common.Hash(post.Logs) {
-		return fmt.Errorf("post state logs hash mismatch: got %x, want %x", logs, post.Logs)
+		return statedb, fmt.Errorf("post state logs hash mismatch: got %x, want %x", logs, post.Logs)
 	}
 	root, _ := statedb.CommitTo(db, config.IsEIP158(block.Number()))
 	if root != common.Hash(post.Root) {
-		return fmt.Errorf("post state root mismatch: got %x, want %x", root, post.Root)
+		return statedb, fmt.Errorf("post state root mismatch: got %x, want %x", root, post.Root)
 	}
-	return nil
+	return statedb, nil
 }
 
 func (t *StateTest) gasLimit(subtest StateSubtest) uint64 {