Updated handleSetRange logic and added some test cases.

src/modules/string/commands.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"github.com/echovault/echovault/src/utils"
 	"net"
-	"strings"
 )
 
 type Plugin struct {
@@ -34,9 +33,9 @@ func handleSetRange(ctx context.Context, cmd []string, server utils.Server, conn
 
 	key := cmd[1]
 
-	offset, ok := utils.AdaptType(cmd[2]).(int64)
+	offset, ok := utils.AdaptType(cmd[2]).(int)
 	if !ok {
-		return nil, errors.New("offset must be integer")
+		return nil, errors.New("offset must be an integer")
 	}
 
 	newStr := cmd[3]
@@ -50,47 +49,47 @@ func handleSetRange(ctx context.Context, cmd []string, server utils.Server, conn
 		return []byte(fmt.Sprintf(":%d\r\n\r\n", len(newStr))), nil
 	}
 
-	str, ok := server.GetValue(key).(string)
-	if !ok {
-		return nil, fmt.Errorf("value at key %s is not a string", key)
-	}
-
 	if _, err := server.KeyLock(ctx, key); err != nil {
 		return nil, err
 	}
 	defer server.KeyUnlock(key)
 
-	if offset >= int64(len(str)) {
+	str, ok := server.GetValue(key).(string)
+	if !ok {
+		return nil, fmt.Errorf("value at key %s is not a string", key)
+	}
+
+	// If the offset  >= length of the string, append the new string to the old one.
+	if offset >= len(str) {
 		newStr = str + newStr
 		server.SetValue(ctx, key, newStr)
 		return []byte(fmt.Sprintf(":%d\r\n\r\n", len(newStr))), nil
 	}
 
+	// If the offset is < 0, prepend the new string to the old one.
 	if offset < 0 {
 		newStr = newStr + str
 		server.SetValue(ctx, key, newStr)
 		return []byte(fmt.Sprintf(":%d\r\n\r\n", len(newStr))), nil
 	}
 
-	if offset == 0 {
-		newStr = newStr + strings.Join(strings.Split(str, "")[1:], "")
-		server.SetValue(ctx, key, newStr)
-		return []byte(fmt.Sprintf(":%d\r\n\r\n", len(newStr))), nil
+	strRunes := []rune(str)
+
+	for i := 0; i < len(newStr); i++ {
+		// If we're still withing the length of the original string, replace the rune in strRunes
+		if offset < len(str) {
+			strRunes[offset] = rune(newStr[i])
+			offset += 1
+			continue
+		}
+		// We are past the length of the original string, append the remainder of newStr to strRunes
+		strRunes = append(strRunes, []rune(newStr)[i:]...)
+		break
 	}
 
-	if offset == int64(len(str))-1 {
-		newStr = strings.Join(strings.Split(str, "")[0:len(str)-1], "") + newStr
-		server.SetValue(ctx, key, newStr)
-		return []byte(fmt.Sprintf(":%d\r\n\r\n", len(newStr))), nil
-	}
+	server.SetValue(ctx, key, string(strRunes))
 
-	strArr := strings.Split(str, "")
-	newStrArr := append(strArr[0:offset], append(strings.Split(newStr, ""), strArr[offset+1:]...)...)
-
-	newStr = strings.Join(newStrArr, "")
-	server.SetValue(ctx, key, newStr)
-
-	return []byte(fmt.Sprintf(":%d\r\n\r\n", len(newStr))), nil
+	return []byte(fmt.Sprintf(":%d\r\n\r\n", len(strRunes))), nil
 }
 
 func handleStrLen(ctx context.Context, cmd []string, server utils.Server, conn *net.Conn) ([]byte, error) {

src/modules/string/commands_test.go

@@ -1,10 +1,153 @@
 package str
 
 import (
+	"bytes"
+	"context"
+	"errors"
+	"github.com/echovault/echovault/src/server"
+	"github.com/echovault/echovault/src/utils"
+	"github.com/tidwall/resp"
+	"strconv"
 	"testing"
 )
 
-func Test_HandleSetRange(t *testing.T) {}
+func Test_HandleSetRange(t *testing.T) {
+	mockServer := server.NewServer(server.Opts{})
+
+	tests := []struct {
+		preset           bool
+		key              string
+		presetValue      string
+		command          []string
+		expectedValue    string
+		expectedResponse int
+		expectedError    error
+	}{
+		{ // Test that SETRANGE on non-existent string creates new string
+			preset:           false,
+			key:              "test1",
+			presetValue:      "",
+			command:          []string{"SETRANGE", "test1", "10", "New String Value"},
+			expectedValue:    "New String Value",
+			expectedResponse: len("New String Value"),
+			expectedError:    nil,
+		},
+		{ // Test SETRANGE with an offset that leads to a longer resulting string
+			preset:           true,
+			key:              "test2",
+			presetValue:      "Original String Value",
+			command:          []string{"SETRANGE", "test2", "16", "Portion Replaced With This New String"},
+			expectedValue:    "Original String Portion Replaced With This New String",
+			expectedResponse: len("Original String Portion Replaced With This New String"),
+			expectedError:    nil,
+		},
+		{ // SETRANGE with negative offset prepends the string
+			preset:           true,
+			key:              "test3",
+			presetValue:      "This is a preset value",
+			command:          []string{"SETRANGE", "test3", "-10", "Prepended "},
+			expectedValue:    "Prepended This is a preset value",
+			expectedResponse: len("Prepended This is a preset value"),
+			expectedError:    nil,
+		},
+		{ // SETRANGE with offset that embeds new string inside the old string
+			preset:           true,
+			key:              "test4",
+			presetValue:      "This is a preset value",
+			command:          []string{"SETRANGE", "test4", "0", "That"},
+			expectedValue:    "That is a preset value",
+			expectedResponse: len("That is a preset value"),
+			expectedError:    nil,
+		},
+		{ // SETRANGE with offset longer than original lengths appends the string
+			preset:           true,
+			key:              "test5",
+			presetValue:      "This is a preset value",
+			command:          []string{"SETRANGE", "test5", "100", " Appended"},
+			expectedValue:    "This is a preset value Appended",
+			expectedResponse: len("This is a preset value Appended"),
+			expectedError:    nil,
+		},
+		{ // SETRANGE with offset on the last character replaces last character with new string
+			preset:           true,
+			key:              "test6",
+			presetValue:      "This is a preset value",
+			command:          []string{"SETRANGE", "test6", strconv.Itoa(len("This is a preset value") - 1), " replaced"},
+			expectedValue:    "This is a preset valu replaced",
+			expectedResponse: len("This is a preset valu replaced"),
+			expectedError:    nil,
+		},
+		{ // Offset not integer
+			preset:           false,
+			command:          []string{"SETRANGE", "key", "offset", "value"},
+			expectedResponse: 0,
+			expectedError:    errors.New("offset must be an integer"),
+		},
+		{ // SETRANGE target is not a string
+			preset:           true,
+			key:              "test-int",
+			presetValue:      "10",
+			command:          []string{"SETRANGE", "test-int", "10", "value"},
+			expectedResponse: 0,
+			expectedError:    errors.New("value at key test-int is not a string"),
+		},
+		{ // Command too short
+			preset:           false,
+			command:          []string{"SETRANGE", "key"},
+			expectedResponse: 0,
+			expectedError:    errors.New(utils.WRONG_ARGS_RESPONSE),
+		},
+		{ // Command too long
+			preset:           false,
+			command:          []string{"SETRANGE", "key", "offset", "value", "value1"},
+			expectedResponse: 0,
+			expectedError:    errors.New(utils.WRONG_ARGS_RESPONSE),
+		},
+	}
+
+	for _, test := range tests {
+		// If there's a preset step, carry it out here
+		if test.preset {
+			if _, err := mockServer.CreateKeyAndLock(context.Background(), test.key); err != nil {
+				t.Error(err)
+			}
+			mockServer.SetValue(context.Background(), test.key, utils.AdaptType(test.presetValue))
+			mockServer.KeyUnlock(test.key)
+		}
+
+		res, err := handleSetRange(context.Background(), test.command, mockServer, nil)
+		if test.expectedError != nil {
+			if err.Error() != test.expectedError.Error() {
+				t.Errorf("expected error \"%s\", got \"%s\"", test.expectedError.Error(), err.Error())
+			}
+			continue
+		}
+		if err != nil {
+			t.Error(err)
+		}
+		rd := resp.NewReader(bytes.NewBuffer(res))
+		rv, _, err := rd.ReadValue()
+		if err != nil {
+			t.Error(err)
+		}
+		if rv.Integer() != test.expectedResponse {
+			t.Errorf("expected response \"%d\", got \"%d\"", test.expectedResponse, rv.Integer())
+		}
+
+		// Get the value from the server and check against the expected value
+		if _, err = mockServer.KeyRLock(context.Background(), test.key); err != nil {
+			t.Error(err)
+		}
+		value, ok := mockServer.GetValue(test.key).(string)
+		if !ok {
+			t.Error("expected string data type, got another type")
+		}
+		if value != test.expectedValue {
+			t.Errorf("expected value \"%s\", got \"%s\"", test.expectedValue, value)
+		}
+		mockServer.KeyRUnlock(test.key)
+	}
+}
 
 func Test_HandleStrLen(t *testing.T) {}