Common POM Mistakes to Avoid

// BAD — assertion inside page object
public class LoginPage extends BasePage {
    public void loginAs(String user, String pass) {
        type(usernameField, user);
        type(passwordField, pass);
        click(loginButton);
        // DO NOT do this!
        Assert.assertTrue(
            driver.findElement(By.id("dashboard")).isDisplayed(),
            "Login failed!");
    }
}

// GOOD — page provides data, test asserts
public class LoginPage extends BasePage {
    public DashboardPage loginAs(String user, String pass) {
        type(usernameField, user);
        type(passwordField, pass);
        click(loginButton);
        return new DashboardPage(driver);
    }
}

@Test
public void testLogin() {
    DashboardPage dashboard = loginPage.loginAs("user", "pass");
    Assert.assertTrue(dashboard.isLoaded());  // Test does the assertion
}

// BAD — test manipulates raw elements
public WebElement getUsernameField() {
    return driver.findElement(By.id("username"));
}

// Test does this:
loginPage.getUsernameField().clear();
loginPage.getUsernameField().sendKeys("user");

// GOOD — expose actions, not elements
public void enterUsername(String username) {
    type(usernameField, username);
}