naming convention for .tpl.php in drupal 7 for custom content type
Overriding node.tpl.php for a specific content type is very simple.  The naming convention is node--machinename.tpl.php. For machinename, use the machine name of the content type with underscores replaced by hyphens. You can inspect the machine name if you navigate to Administration → Structure → Content types.  If you just want the override to apply to a single node (as opposed to all nodes of this content type), add the path replacing all slashes in the path with a double hyphen.

Provided you want to override the node template for path test, your template should be named:

node--basepage--test.tpl.php


No extra actions are required. Just create it (usually by copying it from the theme's node.tpl.php to node--basepage.tpl.php), modify it and place it inside the themes templates/folder. 



Provided you want to override page template page.tpl.php based on the content type being displayed, the naming convention is the same, but you need to do some extra legwork:


Open the template.php file in your theme for editing.
Look for a function called THEME_preprocess_page (replace THEME with the theme's name).
If this function already exists, you will need to add your code to it inside an if-statement that goes at the end of this function, just before the closing bracket  Otherwise, if it doesn't exist, you'll need to create a new function.


This is how the function should look like:

function THEME_preprocess_page(&amp;$vars) {
  // If the function already exists, just leave the code here intact, and add
  // the three lines below to the end.
  if (isset($vars['node']-&gt;type)) {
    $vars['theme_hook_suggestions'][] = 'page__' . $vars['node']-&gt;type;
  }
}


Now, copy the theme's page.tpl.php to a file named page--machinename.tpl.php and place it inside the themes templates/folder. 

Provided you want to override the page template  for path test, your template should be named:

page--basepage--test.tpl.php


for Drupal 7.