Function TestExceedMaxScriptSize

txscript/scriptbuilder_test.go:319–367

TestExceedMaxScriptSize ensures that all of the functions that can be used to add data to a script don't allow the script to exceed the max allowed size.

(t *testing.T)

// to add data to a script don't allow the script to exceed the max allowed
// size.
func TestExceedMaxScriptSize(t *testing.T) {
	t.Parallel()

	// Start off by constructing a max size script.
	builder := NewScriptBuilder()
	builder.Reset().AddFullData(make([]byte, MaxScriptSize-3))
	origScript, err := builder.Script()
	if err != nil {
		t.Fatalf("Unexpected error for max size script: %v", err)
	}

	// Ensure adding data that would exceed the maximum size of the script
	// does not add the data.
	script, err := builder.AddData([]byte{0x00}).Script()
	if _, ok := err.(ErrScriptNotCanonical); !ok || err == nil {
		t.Fatalf("ScriptBuilder.AddData allowed exceeding max script "+
			"size: %v", len(script))
	}
	if !bytes.Equal(script, origScript) {
		t.Fatalf("ScriptBuilder.AddData unexpected modified script - "+
			"got len %d, want len %d", len(script), len(origScript))
	}

	// Ensure adding an opcode that would exceed the maximum size of the
	// script does not add the data.
	builder.Reset().AddFullData(make([]byte, MaxScriptSize-3))
	script, err = builder.AddOp(OP_0).Script()
	if _, ok := err.(ErrScriptNotCanonical); !ok || err == nil {
		t.Fatalf("ScriptBuilder.AddOp unexpected modified script - "+
			"got len %d, want len %d", len(script), len(origScript))
	}
	if !bytes.Equal(script, origScript) {
		t.Fatalf("ScriptBuilder.AddOp unexpected modified script - "+
			"got len %d, want len %d", len(script), len(origScript))
	}

	// Ensure adding an integer that would exceed the maximum size of the
	// script does not add the data.
	builder.Reset().AddFullData(make([]byte, MaxScriptSize-3))
	script, err = builder.AddInt64(0).Script()
	if _, ok := err.(ErrScriptNotCanonical); !ok || err == nil {
		t.Fatalf("ScriptBuilder.AddInt64 unexpected modified script - "+
			"got len %d, want len %d", len(script), len(origScript))
	}
	if !bytes.Equal(script, origScript) {
		t.Fatalf("ScriptBuilder.AddInt64 unexpected modified script - "+
			"got len %d, want len %d", len(script), len(origScript))
	}
}

// TestErroredScript ensures that all of the functions that can be used to add
// data to a script don't modify the script once an error has happened.