{ (define LIBNAME "Testing")
  (include "head.tinc") }

<div>
    <p>
      This teachpack provides four constructs for testing programs:
    </p>
    <p>
      The first three forms create tests:
      <menu>
        <li>
          <code>({(idx check-expect)} test-expression expected-value)</code>
          where <code>test-expression</code> and
          <code>expected-value</code> are both expressions.
          <br/>
          The form evaluates <code>test-expression</code> and then
          verifies that its value is the same as
          <code>expected-value</code>. 
        </li>
        <li>
          <code>({(idx check-within)} test expected delta)</code>
          where <code>test-expression</code>, <code>expected</code>, and
          <code>delta</code> are expressions. 
          <br/>
          The form evaluates <code>test-expression</code> and verifies that
          it produces a real number such that its value is equal to <code>
	    expected</code> plus or minus <code>delta</code>. 
        </li>
        <li>
          <code>({(idx check-error)} test message)</code>
          where <code>test</code> and <code>expected-message</code> are expressions
          <br/>
          The form evaluates <code>test</code> and verifies that it signals
          an error with <code>expected-message</code> as the error report. 
        </li>
      </menu>
        You should place them below the relevant function
        definitions in the Definitions Window. Eventually you should place
        all tests, such as these, at the bottom of the window. 
    </p>

    <p>
      Finally, <code>generate-report</code> is a function that displays
      statistics of running tests: 
      <menu>
        <li>
          <code>{(idx generate-report)} : -&gt; true</code>
          <br/>
          <code>(generate-report)</code> displays the results of all tests
          created with <code>check-expect</code>, <code>check-within</code>,
          and <code>check-error</code>.
        </li>
      </menu>
      Place it at the end of the program or run the expression from the
      Interactions window after clicking RUN. 
    </p>

<b>Example:</b> Place the following seven lines into the Definitions Window
and click RUN: 
<pre>
<code>
(check-expect (+ 1 1) 2)
(check-expect (+ 1 1) 3)

(check-within (+ 1 1) 2.1 .001)
(check-within (+ 1 1) 2.1 .1)

(check-error (+ 1 1) "3")
(check-error (/ 1 0) "/: division by zero")

(generate-report)
</code>
</pre>
 Before you do so, try to figure out which of these tests succeed and which
 fail. After clicking run, you see a separate frame that records how many
 succeeded and failed and detail information about the failures, including
 links for highlighting the source. 
</div>

{(include "foot.tinc")}