update readme & test

README.md

@@ -43,6 +43,8 @@ directory.
 |   `evm`    | Developer utility version of the EVM (Ethereum Virtual Machine) that is capable of running bytecode snippets within a configurable environment and execution mode. Its purpose is to allow isolated, fine-grained debugging of EVM opcodes (e.g. `evm --code 60ff60ff --debug run`).                                                                                                                                                                                                                                               |
 | `rlpdump`  | Developer utility tool to convert binary RLP ([Recursive Length Prefix](https://ethereum.org/en/developers/docs/data-structures-and-encoding/rlp)) dumps (data encoding used by the Ethereum protocol both network as well as consensus wise) to user-friendlier hierarchical representation (e.g. `rlpdump --hex CE0183FFFFFFC4C304050583616263`).                                                                                                                                                                                |
 
+| **`dump-balances`** | Export all non-zero accounts from the current state trie to a file `addresses_balances.txt`. The output is a two-column list (address and ETH balance with 6 decimal places), sorted in descending order by balance. |
+
 ## Running `geth`
 
 Going through all the possible command line flags is out of scope here (please consult our

cmd/geth/dumpbalancescmd_test.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/urfave/cli/v2"
+)
+
+// TestDumpBalancesCommandRegistered checks that our dump-balances
+// command is present in app.Commands with the correct Usage text.
+func TestDumpBalancesCommandRegistered(t *testing.T) {
+	found := false
+	for _, cmd := range app.Commands {
+		if cmd.Name == dumpBalancesCommand.Name {
+			found = true
+			// Ensure that the Usage string mentions "non-zero accounts"
+			if !strings.Contains(cmd.Usage, "non-zero accounts") {
+				t.Errorf("Usage for %q does not include expected text, got %q", cmd.Name, cmd.Usage)
+			}
+			break
+		}
+	}
+	if !found {
+		t.Fatalf("command %q is not registered in app.Commands", dumpBalancesCommand.Name)
+	}
+}
+
+// TestDumpBalancesHelpInProcess simulates running `geth dump-balances --help`
+// in memory and verifies that help output includes the command name and its Usage.
+func TestDumpBalancesHelpInProcess(t *testing.T) {
+	// Create a fresh CLI app with our commands
+	app := cli.NewApp()
+	app.Commands = append([]*cli.Command{}, app.Commands...) // copy existing commands
+	// No need to re-register dumpBalancesCommand because init() already ran
+
+	// Capture the help output in a buffer
+	buf := &bytes.Buffer{}
+	app.Writer = buf
+
+	// Run the help command; cli returns flag.ErrHelp on --help
+	err := app.Run([]string{"geth", "dump-balances", "--help"})
+	if err == nil {
+		t.Fatalf("expected error when running help, got nil")
+	}
+
+	output := buf.String()
+	if !strings.Contains(output, "dump-balances") {
+		t.Errorf("help output missing command name; got:\n%s", output)
+	}
+	if !strings.Contains(output, "non-zero accounts") {
+		t.Errorf("help output missing Usage description; got:\n%s", output)
+	}
+}