Add more tests (and fix some things) for replacecommand

utils/replacecommand.go

@@ -36,7 +36,7 @@ func ExecuteModifications(modifications []ReplaceCommand, fileData string) (stri
 func (m *ReplaceCommand) Execute(fileDataStr string) (string, error) {
 	err := m.Validate(len(fileDataStr))
 	if err != nil {
-		return "", fmt.Errorf("failed to validate modification: %v", err)
+		return fileDataStr, fmt.Errorf("failed to validate modification: %v", err)
 	}
 
 	logger.Trace("Replace pos %d-%d with %q", m.From, m.To, m.With)
@@ -50,5 +50,8 @@ func (m *ReplaceCommand) Validate(maxsize int) error {
 	if m.From > maxsize || m.To > maxsize {
 		return fmt.Errorf("command from or to is greater than replacement length: %v", m)
 	}
+	if m.From < 0 || m.To < 0 {
+		return fmt.Errorf("command from or to is less than 0: %v", m)
+	}
 	return nil
 }

utils/replacecommand_test.go

@@ -2,6 +2,8 @@ package utils
 
 import (
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestReplaceCommandExecute(t *testing.T) {
@@ -178,3 +180,325 @@ func TestReverseOrderExecution(t *testing.T) {
 		t.Errorf("Expected %q, got %q", expected, result)
 	}
 }
+
+// Replace text in the middle of a string with new content
+func TestReplaceCommandExecute_ReplacesTextInMiddle(t *testing.T) {
+	// Arrange
+	cmd := &ReplaceCommand{
+		From: 6,
+		To:   11,
+		With: "replaced",
+	}
+
+	fileContent := "Hello world, how are you?"
+
+	// Act
+	result, err := cmd.Execute(fileContent)
+
+	// Assert
+	assert.NoError(t, err)
+	assert.Equal(t, "Hello replaced, how are you?", result)
+}
+
+// Replace with empty string (deletion)
+func TestReplaceCommandExecute_DeletesText(t *testing.T) {
+	// Arrange
+	cmd := &ReplaceCommand{
+		From: 6,
+		To:   11,
+		With: "",
+	}
+
+	fileContent := "Hello world, how are you?"
+
+	// Act
+	result, err := cmd.Execute(fileContent)
+
+	// Assert
+	assert.NoError(t, err)
+	assert.Equal(t, "Hello , how are you?", result)
+}
+
+// Replace with longer string than original segment
+func TestReplaceCommandExecute_WithLongerString(t *testing.T) {
+	// Arrange
+	cmd := &ReplaceCommand{
+		From: 6,
+		To:   11,
+		With: "longerreplacement",
+	}
+
+	fileContent := "Hello world, how are you?"
+
+	// Act
+	result, err := cmd.Execute(fileContent)
+
+	// Assert
+	assert.NoError(t, err)
+	assert.Equal(t, "Hello longerreplacement, how are you?", result)
+}
+
+// From and To values are the same (zero-length replacement)
+func TestReplaceCommandExecute_ZeroLengthReplacement(t *testing.T) {
+	// Arrange
+	cmd := &ReplaceCommand{
+		From: 5,
+		To:   5,
+		With: "inserted",
+	}
+
+	fileContent := "Hello world"
+
+	// Act
+	result, err := cmd.Execute(fileContent)
+
+	// Assert
+	assert.NoError(t, err)
+	assert.Equal(t, "Helloinserted world", result)
+}
+
+// From value is greater than To value
+func TestReplaceCommandExecute_FromGreaterThanTo(t *testing.T) {
+	// Arrange
+	cmd := &ReplaceCommand{
+		From: 10,
+		To:   5,
+		With: "replaced",
+	}
+
+	fileContent := "Hello world, how are you?"
+
+	// Act
+	result, err := cmd.Execute(fileContent)
+
+	// Assert
+	assert.Error(t, err)
+	assert.Equal(t, "Hello world, how are you?", result)
+}
+
+// From or To values exceed string length
+func TestReplaceCommandExecute_FromOrToExceedsLength(t *testing.T) {
+	// Arrange
+	cmd := &ReplaceCommand{
+		From: 5,
+		To:   50, // Exceeds the length of the fileContent
+		With: "replaced",
+	}
+
+	fileContent := "Hello world"
+
+	// Act
+	result, err := cmd.Execute(fileContent)
+
+	// Assert
+	assert.Error(t, err)
+	assert.Equal(t, "Hello world", result)
+}
+
+// From or To values are negative
+func TestReplaceCommandExecute_NegativeFromOrTo(t *testing.T) {
+	// Arrange
+	cmd := &ReplaceCommand{
+		From: -1,
+		To:   10,
+		With: "replaced",
+	}
+
+	fileContent := "Hello world, how are you?"
+
+	// Act
+	result, err := cmd.Execute(fileContent)
+
+	// Assert
+	assert.Error(t, err)
+	assert.Equal(t, "Hello world, how are you?", result)
+}
+
+// Modifications are applied in reverse order (from highest to lowest 'From' value)
+func TestExecuteModificationsAppliesInReverseOrder(t *testing.T) {
+	// Setup test data
+	fileData := "This is a test string for replacements"
+
+	modifications := []ReplaceCommand{
+		{From: 0, To: 4, With: "That"},
+		{From: 10, To: 14, With: "sample"},
+		{From: 26, To: 38, With: "modifications"},
+	}
+
+	// Execute the function
+	result, executed := ExecuteModifications(modifications, fileData)
+
+	// Verify results
+	expectedResult := "That is a sample string for modifications"
+	if result != expectedResult {
+		t.Errorf("Expected result to be %q, but got %q", expectedResult, result)
+	}
+
+	if executed != 3 {
+		t.Errorf("Expected 3 modifications to be executed, but got %d", executed)
+	}
+}
+
+// One or more modifications fail but others succeed
+func TestExecuteModificationsWithPartialFailures(t *testing.T) {
+	// Setup test data
+	fileData := "This is a test string for replacements"
+
+	// Create a custom ReplaceCommand implementation that will fail
+	failingCommand := ReplaceCommand{
+		From: 15,
+		To:   10, // Invalid range (To < From) to cause failure
+		With: "will fail",
+	}
+
+	// Valid commands
+	validCommand1 := ReplaceCommand{
+		From: 0,
+		To:   4,
+		With: "That",
+	}
+
+	validCommand2 := ReplaceCommand{
+		From: 26,
+		To:   38,
+		With: "modifications",
+	}
+
+	modifications := []ReplaceCommand{failingCommand, validCommand1, validCommand2}
+
+	// Execute the function
+	result, executed := ExecuteModifications(modifications, fileData)
+
+	// Verify results
+	expectedResult := "That is a test string for modifications"
+	if result != expectedResult {
+		t.Errorf("Expected result to be %q, but got %q", expectedResult, result)
+	}
+
+	// Only 2 out of 3 modifications should succeed
+	if executed != 2 {
+		t.Errorf("Expected 2 modifications to be executed successfully, but got %d", executed)
+	}
+}
+
+// All valid modifications are executed and the modified string is returned
+func TestExecuteModificationsAllValid(t *testing.T) {
+	// Setup test data
+	fileData := "Hello world, this is a test"
+
+	modifications := []ReplaceCommand{
+		{From: 0, To: 5, With: "Hi"},
+		{From: 18, To: 20, With: "was"},
+		{From: 21, To: 27, With: "an example"},
+	}
+
+	// Execute the function
+	result, executed := ExecuteModifications(modifications, fileData)
+
+	// Verify results
+	expectedResult := "Hi world, this was an example"
+	if result != expectedResult {
+		t.Errorf("Expected result to be %q, but got %q", expectedResult, result)
+	}
+
+	if executed != 3 {
+		t.Errorf("Expected 3 modifications to be executed, but got %d", executed)
+	}
+}
+
+// The count of successfully executed modifications is returned
+func TestExecuteModificationsReturnsCorrectCount(t *testing.T) {
+	// Setup test data
+	fileData := "Initial text for testing"
+
+	modifications := []ReplaceCommand{
+		{From: 0, To: 7, With: "Final"},
+		{From: 12, To: 16, With: "example"},
+		{From: 17, To: 24, With: "process"},
+	}
+
+	// Execute the function
+	_, executed := ExecuteModifications(modifications, fileData)
+
+	// Verify the count of executed modifications
+	expectedExecuted := 3
+	if executed != expectedExecuted {
+		t.Errorf("Expected %d modifications to be executed, but got %d", expectedExecuted, executed)
+	}
+}
+
+// Empty modifications list returns the original string with zero executed count
+func TestExecuteModificationsWithEmptyList(t *testing.T) {
+	// Setup test data
+	fileData := "This is a test string for replacements"
+
+	modifications := []ReplaceCommand{}
+
+	// Execute the function
+	result, executed := ExecuteModifications(modifications, fileData)
+
+	// Verify results
+	if result != fileData {
+		t.Errorf("Expected result to be %q, but got %q", fileData, result)
+	}
+
+	if executed != 0 {
+		t.Errorf("Expected 0 modifications to be executed, but got %d", executed)
+	}
+}
+
+// Modifications with identical 'From' values
+func TestExecuteModificationsWithIdenticalFromValues(t *testing.T) {
+	// Setup test data
+	fileData := "This is a test string for replacements"
+
+	modifications := []ReplaceCommand{
+		{From: 10, To: 14, With: "sample"},
+		{From: 10, To: 14, With: "example"},
+		{From: 26, To: 38, With: "modifications"},
+	}
+
+	// Execute the function
+	result, executed := ExecuteModifications(modifications, fileData)
+
+	// Verify results
+	// Yes, it's mangled, yes, it's intentional
+	// Every subsequent command works with the modified contents of the previous command
+	// So by the time we get to "example" the indices have already eaten into "sample"... In fact they have eaten into "samp", "le" is left
+	// So we prepend "example" and end up with "examplele"
+	// Whether sample or example goes first here is irrelevant to us
+	// But it just so happens that sample goes first, so we end up with "examplele"
+	expectedResult := "This is a examplele string for modifications"
+	if result != expectedResult {
+		t.Errorf("Expected result to be %q, but got %q", expectedResult, result)
+	}
+
+	if executed != 3 {
+		t.Errorf("Expected 3 modifications to be executed, but got %d", executed)
+	}
+}
+
+// Modifications that would affect each other if not sorted properly
+func TestExecuteModificationsHandlesOverlappingRanges(t *testing.T) {
+	// Setup test data
+	fileData := "The quick brown fox jumps over the lazy dog"
+
+	modifications := []ReplaceCommand{
+		{From: 4, To: 9, With: "slow"},
+		{From: 10, To: 15, With: "red"},
+		{From: 16, To: 19, With: "cat"},
+	}
+
+	// Execute the function
+	result, executed := ExecuteModifications(modifications, fileData)
+
+	// Verify results
+	expectedResult := "The slow red cat jumps over the lazy dog"
+	if result != expectedResult {
+		t.Errorf("Expected result to be %q, but got %q", expectedResult, result)
+	}
+
+	if executed != 3 {
+		t.Errorf("Expected 3 modifications to be executed, but got %d", executed)
+	}
+}