How do you handle configuration management in a Selenium framework?

# src/test/resources/config/config.properties

# Browser
browser=chrome
headless=false

# Timeouts (seconds)
implicit.wait=10
explicit.wait=15
page.load.timeout=30

# URLs
base.url=https://staging.automateqa.online
api.base.url=https://api.staging.automateqa.online

# Test data
test.user.email=testuser@automateqa.com
test.user.password=Test@123

# Reports
report.dir=test-output/reports
screenshot.dir=test-output/screenshots

src/test/resources/config/
├── config.properties      ← default (staging)
├── qa.properties          ← QA environment
└── prod.properties        ← production (read-only tests)

# qa.properties
base.url=https://qa.automateqa.online
test.user.email=qa_test@automateqa.com

// config/ConfigReader.java
public class ConfigReader {
    private static Properties properties;

    // Singleton — load only once
    private static Properties getProperties() {
        if (properties == null) {
            properties = new Properties();
            // env can be passed via Maven: -Denv=qa
            String env = System.getProperty("env", "config");
            String path = "src/test/resources/config/" + env + ".properties";
            try (FileInputStream fis = new FileInputStream(path)) {
                properties.load(fis);
            } catch (IOException e) {
                throw new RuntimeException("Cannot load: " + path, e);
            }
        }
        return properties;
    }

    // System properties override file values (great for CI/CD)
    public static String get(String key) {
        return System.getProperty(key, getProperties().getProperty(key));
    }

    public static int getInt(String key) {
        return Integer.parseInt(get(key));
    }

    public static boolean getBoolean(String key) {
        return Boolean.parseBoolean(get(key));
    }

    // Typed getters for common config
    public static String getBrowser()     { return get("browser"); }
    public static String getBaseUrl()     { return get("base.url"); }
    public static boolean isHeadless()    { return getBoolean("headless"); }
    public static int getExplicitWait()   { return getInt("explicit.wait"); }
}

// DriverManager reads browser type from config
String browser = ConfigReader.getBrowser();

// BaseTest reads URL from config
driver.get(ConfigReader.getBaseUrl());

// Tests use credentials from config
loginPage.login(
    ConfigReader.get("test.user.email"),
    ConfigReader.get("test.user.password")
);

# Switch environment via Maven system property
mvn test -Denv=qa -Dbrowser=firefox -Dheadless=true

# In GitHub Actions
- run: mvn test
  env:
    # These override config.properties values
  with:
  # Pass as system property
- run: mvn test -Denv=qa -Dbase.url=${{ secrets.QA_URL }} -Dheadless=true

<suite name="Automation Suite">
    <parameter name="browser" value="chrome"/>
    <parameter name="env"     value="staging"/>

    <test name="Smoke Tests">
        <classes>
            <class name="com.automateqa.tests.LoginTest"/>
        </classes>
    </test>
</suite>

// Read TestNG parameter in BaseTest
@Parameters({"browser", "env"})
@BeforeMethod
public void setUp(@Optional("chrome") String browser,
                  @Optional("staging") String env) {
    System.setProperty("browser", browser);
    System.setProperty("env",     env);
    DriverManager.init();
}