cmd/evm: add tests for evm t8n (#23507)

cmd/evm/README.md

@@ -208,7 +208,7 @@ Example:
   ]
 }
 ```
-When applying this, using a reward of `0x08`
+When applying this, using a reward of `0x80`
 Output:
 ```json
 {

cmd/evm/internal/t8ntool/transition.go

@@ -65,10 +65,15 @@ func (n *NumberedError) Error() string {
 	return fmt.Sprintf("ERROR(%d): %v", n.errorCode, n.err.Error())
 }
 
-func (n *NumberedError) Code() int {
+func (n *NumberedError) ExitCode() int {
 	return n.errorCode
 }
 
+// compile-time conformance test
+var (
+	_ cli.ExitCoder = (*NumberedError)(nil)
+)
+
 type input struct {
 	Alloc core.GenesisAlloc `json:"alloc,omitempty"`
 	Env   *stEnv            `json:"env,omitempty"`

cmd/evm/main.go

@@ -195,7 +195,7 @@ func main() {
 	if err := app.Run(os.Args); err != nil {
 		code := 1
 		if ec, ok := err.(*t8ntool.NumberedError); ok {
-			code = ec.Code()
+			code = ec.ExitCode()
 		}
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(code)

cmd/evm/t8n_test.go

+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/docker/docker/pkg/reexec"
+	"github.com/ethereum/go-ethereum/internal/cmdtest"
+)
+
+func TestMain(m *testing.M) {
+	// Run the app if we've been exec'd as "ethkey-test" in runEthkey.
+	reexec.Register("evm-test", func() {
+		if err := app.Run(os.Args); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		os.Exit(0)
+	})
+	// check if we have been reexec'd
+	if reexec.Init() {
+		return
+	}
+	os.Exit(m.Run())
+}
+
+type testT8n struct {
+	*cmdtest.TestCmd
+}
+
+type t8nInput struct {
+	inAlloc  string
+	inTxs    string
+	inEnv    string
+	stFork   string
+	stReward string
+}
+
+func (args *t8nInput) get(base string) []string {
+	var out []string
+	if opt := args.inAlloc; opt != "" {
+		out = append(out, "--input.alloc")
+		out = append(out, fmt.Sprintf("%v/%v", base, opt))
+	}
+	if opt := args.inTxs; opt != "" {
+		out = append(out, "--input.txs")
+		out = append(out, fmt.Sprintf("%v/%v", base, opt))
+	}
+	if opt := args.inEnv; opt != "" {
+		out = append(out, "--input.env")
+		out = append(out, fmt.Sprintf("%v/%v", base, opt))
+	}
+	if opt := args.stFork; opt != "" {
+		out = append(out, "--state.fork", opt)
+	}
+	if opt := args.stReward; opt != "" {
+		out = append(out, "--state.reward", opt)
+	}
+	return out
+}
+
+type t8nOutput struct {
+	alloc  bool
+	result bool
+	body   bool
+}
+
+func (args *t8nOutput) get() (out []string) {
+	out = append(out, "t8n")
+	if args.body {
+		out = append(out, "--output.body", "stdout")
+	} else {
+		out = append(out, "--output.body", "") // empty means ignore
+	}
+	if args.result {
+		out = append(out, "--output.result", "stdout")
+	} else {
+		out = append(out, "--output.result", "")
+	}
+	if args.alloc {
+		out = append(out, "--output.alloc", "stdout")
+	} else {
+		out = append(out, "--output.alloc", "")
+	}
+	return out
+}
+
+func TestT8n(t *testing.T) {
+	tt := new(testT8n)
+	tt.TestCmd = cmdtest.NewTestCmd(t, tt)
+	for i, tc := range []struct {
+		base        string
+		input       t8nInput
+		output      t8nOutput
+		expExitCode int
+		expOut      string
+	}{
+		{ // Test exit (3) on bad config
+			base: "./testdata/1",
+			input: t8nInput{
+				"alloc.json", "txs.json", "env.json", "Frontier+1346", "",
+			},
+			output:      t8nOutput{alloc: true, result: true},
+			expExitCode: 3,
+		},
+		{
+			base: "./testdata/1",
+			input: t8nInput{
+				"alloc.json", "txs.json", "env.json", "Byzantium", "",
+			},
+			output: t8nOutput{alloc: true, result: true},
+			expOut: "exp.json",
+		},
+		{ // blockhash test
+			base: "./testdata/3",
+			input: t8nInput{
+				"alloc.json", "txs.json", "env.json", "Berlin", "",
+			},
+			output: t8nOutput{alloc: true, result: true},
+			expOut: "exp.json",
+		},
+		{ // missing blockhash test
+			base: "./testdata/4",
+			input: t8nInput{
+				"alloc.json", "txs.json", "env.json", "Berlin", "",
+			},
+			output:      t8nOutput{alloc: true, result: true},
+			expExitCode: 4,
+		},
+		{ // Ommer test
+			base: "./testdata/5",
+			input: t8nInput{
+				"alloc.json", "txs.json", "env.json", "Byzantium", "0x80",
+			},
+			output: t8nOutput{alloc: true, result: true},
+			expOut: "exp.json",
+		},
+		{ // Sign json transactions
+			base: "./testdata/13",
+			input: t8nInput{
+				"alloc.json", "txs.json", "env.json", "London", "",
+			},
+			output: t8nOutput{body: true},
+			expOut: "exp.json",
+		},
+		{ // Already signed transactions
+			base: "./testdata/13",
+			input: t8nInput{
+				"alloc.json", "signed_txs.rlp", "env.json", "London", "",
+			},
+			output: t8nOutput{result: true},
+			expOut: "exp2.json",
+		},
+		{ // Difficulty calculation - no uncles
+			base: "./testdata/14",
+			input: t8nInput{
+				"alloc.json", "txs.json", "env.json", "London", "",
+			},
+			output: t8nOutput{result: true},
+			expOut: "exp.json",
+		},
+		{ // Difficulty calculation - with uncles
+			base: "./testdata/14",
+			input: t8nInput{
+				"alloc.json", "txs.json", "env.uncles.json", "London", "",
+			},
+			output: t8nOutput{result: true},
+			expOut: "exp2.json",
+		},
+	} {
+
+		args := append(tc.output.get(), tc.input.get(tc.base)...)
+		tt.Run("evm-test", args...)
+		tt.Logf("args: %v\n", strings.Join(args, " "))
+		// Compare the expected output, if provided
+		if tc.expOut != "" {
+			want, err := os.ReadFile(fmt.Sprintf("%v/%v", tc.base, tc.expOut))
+			if err != nil {
+				t.Fatalf("test %d: could not read expected output: %v", i, err)
+			}
+			have := tt.Output()
+			ok, err := cmpJson(have, want)
+			switch {
+			case err != nil:
+				t.Fatalf("test %d, json parsing failed: %v", i, err)
+			case !ok:
+				t.Fatalf("test %d: output wrong, have \n%v\nwant\n%v\n", i, string(have), string(want))
+			}
+		}
+		tt.WaitExit()
+		if have, want := tt.ExitStatus(), tc.expExitCode; have != want {
+			t.Fatalf("test %d: wrong exit code, have %d, want %d", i, have, want)
+		}
+	}
+}
+
+// cmpJson compares the JSON in two byte slices.
+func cmpJson(a, b []byte) (bool, error) {
+	var j, j2 interface{}
+	if err := json.Unmarshal(a, &j); err != nil {
+		return false, err
+	}
+	if err := json.Unmarshal(b, &j2); err != nil {
+		return false, err
+	}
+	return reflect.DeepEqual(j2, j), nil
+}

cmd/evm/testdata/1/exp.json

+{
+  "alloc": {
+    "0x8a8eafb1cf62bfbeb1741769dae1a9dd47996192": {
+      "balance": "0xfeed1a9d",
+      "nonce": "0x1"
+    },
+    "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b": {
+      "balance": "0x5ffd4878be161d74",
+      "nonce": "0xac"
+    },
+    "0xc94f5374fce5edbc8e2a8697c15331677e6ebf0b": {
+      "balance": "0xa410"
+    }
+  },
+  "result": {
+    "stateRoot": "0x84208a19bc2b46ada7445180c1db162be5b39b9abc8c0a54b05d32943eae4e13",
+    "txRoot": "0xc4761fd7b87ff2364c7c60b6c5c8d02e522e815328aaea3f20e3b7b7ef52c42d",
+    "receiptRoot": "0x056b23fbba480696b65fe5a59b8f2148a1299103c4f57df839233af2cf4ca2d2",
+    "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+    "receipts": [
+      {
+        "root": "0x",
+        "status": "0x1",
+        "cumulativeGasUsed": "0x5208",
+        "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "logs": null,
+        "transactionHash": "0x0557bacce3375c98d806609b8d5043072f0b6a8bae45ae5a67a00d3a1a18d673",
+        "contractAddress": "0x0000000000000000000000000000000000000000",
+        "gasUsed": "0x5208",
+        "blockHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+        "transactionIndex": "0x0"
+      }
+    ],
+    "rejected": [
+      {
+        "index": 1,
+        "error": "nonce too low: address 0x8A8eAFb1cf62BfBeb1741769DAE1a9dd47996192, tx: 0 state: 1"
+      }
+    ],
+    "currentDifficulty": "0x20000"
+  }
+}
\ No newline at end of file

cmd/evm/testdata/13/exp.json

+{
+  "body": "0xf8d2b86702f864010180820fa08284d09411111111111111111111111111111111111111118080c001a0b7dfab36232379bb3d1497a4f91c1966b1f932eae3ade107bf5d723b9cb474e0a06261c359a10f2132f126d250485b90cf20f30340801244a08ef6142ab33d1904b86702f864010280820fa08284d09411111111111111111111111111111111111111118080c080a0d4ec563b6568cd42d998fc4134b36933c6568d01533b5adf08769270243c6c7fa072bf7c21eac6bbeae5143371eef26d5e279637f3bd73482b55979d76d935b1e9"
+}

cmd/evm/testdata/13/exp2.json

+{
+  "result": {
+    "stateRoot": "0xe4b924a6adb5959fccf769d5b7bb2f6359e26d1e76a2443c5a91a36d826aef61",
+    "txRoot": "0x013509c8563d41c0ae4bf38f2d6d19fc6512a1d0d6be045079c8c9f68bf45f9d",
+    "receiptRoot": "0xa532a08aa9f62431d6fe5d924951b8efb86ed3c54d06fee77788c3767dd13420",
+    "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+    "receipts": [
+      {
+        "type": "0x2",
+        "root": "0x",
+        "status": "0x0",
+        "cumulativeGasUsed": "0x84d0",
+        "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "logs": null,
+        "transactionHash": "0xa98a24882ea90916c6a86da650fbc6b14238e46f0af04a131ce92be897507476",
+        "contractAddress": "0x0000000000000000000000000000000000000000",
+        "gasUsed": "0x84d0",
+        "blockHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+        "transactionIndex": "0x0"
+      },
+      {
+        "type": "0x2",
+        "root": "0x",
+        "status": "0x0",
+        "cumulativeGasUsed": "0x109a0",
+        "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "logs": null,
+        "transactionHash": "0x36bad80acce7040c45fd32764b5c2b2d2e6f778669fb41791f73f546d56e739a",
+        "contractAddress": "0x0000000000000000000000000000000000000000",
+        "gasUsed": "0x84d0",
+        "blockHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+        "transactionIndex": "0x1"
+      }
+    ],
+    "currentDifficulty": "0x20000"
+  }
+}

cmd/evm/testdata/13/signed_txs.rlp

+"0xf8d2b86702f864010180820fa08284d09411111111111111111111111111111111111111118080c001a0b7dfab36232379bb3d1497a4f91c1966b1f932eae3ade107bf5d723b9cb474e0a06261c359a10f2132f126d250485b90cf20f30340801244a08ef6142ab33d1904b86702f864010280820fa08284d09411111111111111111111111111111111111111118080c080a0d4ec563b6568cd42d998fc4134b36933c6568d01533b5adf08769270243c6c7fa072bf7c21eac6bbeae5143371eef26d5e279637f3bd73482b55979d76d935b1e9"
\ No newline at end of file

cmd/evm/testdata/14/env.json

@@ -3,7 +3,7 @@
   "currentGasLimit": "0x750a163df65e8a",
   "currentBaseFee": "0x500",
   "currentNumber": "12800000",
-  "currentTimestamp": "10015",
+  "currentTimestamp": "100015",
   "parentTimestamp" : "99999",
   "parentDifficulty" : "0x2000000000000"
 }

cmd/evm/testdata/14/env.uncles.json

@@ -3,7 +3,7 @@
   "currentGasLimit": "0x750a163df65e8a",
   "currentBaseFee": "0x500",
   "currentNumber": "12800000",
-  "currentTimestamp": "10035",
+  "currentTimestamp": "100035",
   "parentTimestamp" : "99999",
   "parentDifficulty" : "0x2000000000000",
   "parentUncleHash" : "0x000000000000000000000000000000000000000000000000000000000000beef"

cmd/evm/testdata/14/exp.json

+{
+  "result": {
+    "stateRoot": "0x6f058887ca01549716789c380ede95aecc510e6d1fdc4dbf67d053c7c07f4bdc",
+    "txRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "receiptRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+    "currentDifficulty": "0x2000020000000",
+    "receipts": []
+  }
+}
\ No newline at end of file

cmd/evm/testdata/14/exp2.json

+{
+  "result": {
+    "stateRoot": "0x6f058887ca01549716789c380ede95aecc510e6d1fdc4dbf67d053c7c07f4bdc",
+    "txRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "receiptRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+    "receipts": [],
+    "currentDifficulty": "0x1ff8020000000"
+  }
+}
\ No newline at end of file

cmd/evm/testdata/14/readme.md

@@ -5,9 +5,9 @@ This test shows how the `evm t8n` can be used to calculate the (ethash) difficul
 Calculating it (with an empty set of txs) using `London` rules (and no provided unclehash for the parent block):
 ```
 [user@work evm]$ ./evm t8n --input.alloc=./testdata/14/alloc.json --input.txs=./testdata/14/txs.json --input.env=./testdata/14/env.json --output.result=stdout --state.fork=London
-INFO [08-08|17:35:46.876] Trie dumping started                     root=6f0588..7f4bdc
-INFO [08-08|17:35:46.876] Trie dumping complete                    accounts=2 elapsed="89.313µs"
-INFO [08-08|17:35:46.877] Wrote file                               file=alloc.json
+INFO [08-30|20:43:09.352] Trie dumping started                     root=6f0588..7f4bdc
+INFO [08-30|20:43:09.352] Trie dumping complete                    accounts=2 elapsed="82.533µs"
+INFO [08-30|20:43:09.352] Wrote file                               file=alloc.json
 {
   "result": {
     "stateRoot": "0x6f058887ca01549716789c380ede95aecc510e6d1fdc4dbf67d053c7c07f4bdc",
@@ -16,16 +16,16 @@ INFO [08-08|17:35:46.877] Wrote file                               file=alloc.js
     "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
     "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
     "receipts": [],
-  "currentDifficulty": 3311729559732224
+    "currentDifficulty": "0x2000020000000"
   }
 }
 ```
 Same thing, but this time providing a non-empty (and non-`emptyKeccak`) unclehash, which leads to a slightly different result:
 ```
 [user@work evm]$ ./evm t8n --input.alloc=./testdata/14/alloc.json --input.txs=./testdata/14/txs.json --input.env=./testdata/14/env.uncles.json --output.result=stdout --state.fork=London
-INFO [08-08|17:35:49.232] Trie dumping started                     root=6f0588..7f4bdc
-INFO [08-08|17:35:49.232] Trie dumping complete                    accounts=2 elapsed="83.069µs"
-INFO [08-08|17:35:49.233] Wrote file                               file=alloc.json
+INFO [08-30|20:44:33.102] Trie dumping started                     root=6f0588..7f4bdc
+INFO [08-30|20:44:33.102] Trie dumping complete                    accounts=2 elapsed="72.91µs"
+INFO [08-30|20:44:33.102] Wrote file                               file=alloc.json
 {
   "result": {
     "stateRoot": "0x6f058887ca01549716789c380ede95aecc510e6d1fdc4dbf67d053c7c07f4bdc",
@@ -34,7 +34,7 @@ INFO [08-08|17:35:49.233] Wrote file                               file=alloc.js
     "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
     "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
     "receipts": [],
-  "currentDifficulty": 3311179803918336
+    "currentDifficulty": "0x1ff8020000000"
   }
 }
 ```

cmd/evm/testdata/15/signed_txs.rlp.json

+{
+ "txsRlp" : "0xf8d2b86702f864010180820fa08284d09411111111111111111111111111111111111111118080c001a0b7dfab36232379bb3d1497a4f91c1966b1f932eae3ade107bf5d723b9cb474e0a06261c359a10f2132f126d250485b90cf20f30340801244a08ef6142ab33d1904b86702f864010280820fa08284d09411111111111111111111111111111111111111118080c080a0d4ec563b6568cd42d998fc4134b36933c6568d01533b5adf08769270243c6c7fa072bf7c21eac6bbeae5143371eef26d5e279637f3bd73482b55979d76d935b1e9"
+}
+

cmd/evm/testdata/3/exp.json

+{
+  "alloc": {
+    "0x095e7baea6a6c7c4c2dfeb977efac326af552d87": {
+      "code": "0x600140",
+      "balance": "0xde0b6b3a76586a0"
+    },
+    "0x2adc25665018aa1fe0e6bc666dac8fc2697ff9ba": {
+      "balance": "0x521f"
+    },
+    "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b": {
+      "balance": "0xde0b6b3a7622741",
+      "nonce": "0x1"
+    }
+  },
+  "result": {
+    "stateRoot": "0xb7341da3f9f762a6884eaa186c32942734c146b609efee11c4b0214c44857ea1",
+    "txRoot": "0x75e61774a2ff58cbe32653420256c7f44bc715715a423b0b746d5c622979af6b",
+    "receiptRoot": "0xd0d26df80374a327c025d405ebadc752b1bbd089d864801ae78ab704bcad8086",
+    "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+    "receipts": [
+      {
+        "root": "0x",
+        "status": "0x1",
+        "cumulativeGasUsed": "0x521f",
+        "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "logs": null,
+        "transactionHash": "0x72fadbef39cd251a437eea619cfeda752271a5faaaa2147df012e112159ffb81",
+        "contractAddress": "0x0000000000000000000000000000000000000000",
+        "gasUsed": "0x521f",
+        "blockHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+        "transactionIndex": "0x0"
+      }
+    ],
+    "currentDifficulty": "0x20000"
+  }
+}

cmd/evm/testdata/5/exp.json

+{
+  "alloc": {
+    "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa": {
+      "balance": "0x88"
+    },
+    "0xbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb": {
+      "balance": "0x70"
+    },
+    "0xcccccccccccccccccccccccccccccccccccccccc": {
+      "balance": "0x60"
+    }
+  },
+  "result": {
+    "stateRoot": "0xa7312add33811645c6aa65d928a1a4f49d65d448801912c069a0aa8fe9c1f393",
+    "txRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "receiptRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+    "receipts": [],
+    "currentDifficulty": "0x20000"
+  }
+}

internal/cmdtest/test_cmd.go

@@ -118,6 +118,13 @@ func (tt *TestCmd) Expect(tplsource string) {
 	tt.Logf("Matched stdout text:\n%s", want)
 }
 
+// Output reads all output from stdout, and returns the data.
+func (tt *TestCmd) Output() []byte {
+	var buf []byte
+	tt.withKillTimeout(func() { buf, _ = io.ReadAll(tt.stdout) })
+	return buf
+}
+
 func (tt *TestCmd) matchExactOutput(want []byte) error {
 	buf := make([]byte, len(want))
 	n := 0