src/devices/tech/test_infra/tradefed/fundamentals/options.jd

page.title=Option Handling
@jd:body

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<p>Option handling lies at the heart of Trade Federation's modular approach.  In particular, options
are the mechanism by which the Developer, Integrator, and Test Runner can work together without
having to duplicate each-other's work.  Put simply, our implementation of option handling allows the
Developer to mark a Java class member as being configurable, at which point the value of that member
may be augmented or overridden by the Integrator, and may be subsequently augmented or overridden by
the Test Runner.  This mechanism works for all Java intrinsic types, as well as for any
<code>Map</code>s or <code>Collection</code>s of intrinsic types.</p>

<p><em>Note:</em> the option-handling mechanism only works for classes implementing one of the
interfaces included in the <a href="lifecycle.html">Test Lifecycle</a>, and only when that class is
<em>instantiated</em> by the lifecycle machinery.</p>

<h2>Developer</h2>
<p>To start off, the developer marks a member with the
<code><a href="https://android.googlesource.com/platform/tools/tradefederation/+/master/src/com/android/tradefed/config/Option.java"
>@Option</a></code> annotation.  <!-- note: javadoc for the Option class is broken -->
They specify (at a minimum) the <code>name</code> and <code>description</code> values, which
specify the argument name associated with that Option, and the description that will be displayed on
the TF console when the command is run with <code>--help</code> or <code>--help-all</code>.</p>

<p>As an example, let's say we want to build a functional phone test which will dial a variety of
phone numbers, and will expect to receive a sequence of DTMF tones from each number after it
connects.</p>
<code><pre>public class PhoneCallFuncTest extends IRemoteTest {
    &#64;Option(name = "timeout", description = "How long to wait for connection, in millis")
    private long mWaitTime = 30 * 1000;  // 30 seconds

    &#64;Option(name = "call", description = "Key: Phone number to attempt.  " +
            "Value: DTMF to expect.  May be repeated.")
    private Map&lt;String, String&gt; mCalls = new HashMap&lt;String, String&gt;;

    public PhoneCallFuncTest() {
        mCalls.add("123-456-7890", "01134");  // default
    }</pre></code>

<p>That's all that's required for the Developer to set up two points of configuration for that
test.  They could then go off and use <code>mWaitTime</code> and <code>mCalls</code> as normal,
without paying much attention to the fact that they're configurable.  Because the
<code>@Option</code> fields are set after the class is instantiated, but before the
<code>run</code> method is called, that provides an easy way for implementors to set up defaults for
or perform some kind of filtering on <code>Map</code> and <code>Collection</code> fields, which are
otherwise append-only.</p>

<h2>Integrator</h2>
<p>The Integrator works in the world of Configurations, which are written in XML.  The config format
allows the Integrator to set (or append) a value for any <code>@Option</code> field.  For instance,
suppose the Integrator wanted to define a lower-latency test that calls the default number, as well
as a long-running test that calls a variety of numbers.  They could create a pair of configurations
that might look like the following:</p>

<code><pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;configuration description="low-latency default test; low-latency.xml"&gt;
    &lt;test class="com.example.PhoneCallFuncTest"&gt;
        &lt;option name="timeout" value="5000" /&gt;
    &lt;/test&gt;
&lt;/configuration&gt;</pre></code>

<code><pre>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;configuration description="call a bunch of numbers; many-numbers.xml"&gt;
    &lt;test class="com.example.PhoneCallFuncTest"&gt;
        &lt;option name="call" key="111-111-1111" value="#*#*TEST1*#*#" /&gt;
        &lt;option name="call" key="222-222-2222" value="#*#*TEST2*#*#" /&gt;
        &lt;!-- ... --&gt;
    &lt;/test&gt;
&lt;/configuration&gt;</pre></code>

<h2>Test Runner</h2>
<p>The Test Runner also has access to these configuration points via the Trade Federation console.
First and foremost, they will run a Command (that is, a config and all of its arguments) with the
<code>run command &lt;name&gt;</code> instruction (or <code>run &lt;name&gt;</code> for short).
Beyond that, they can specify any list of arguments are part of the command, which may replace or
append to fields specified by Lifecycle Objects within each config.</p>

<p>To run the low-latency test with the <code>many-numbers</code> phone numbers, the Test Runner
could execute:</p>
<code><pre>tf >run low-latency.xml --call 111-111-1111 #*#*TEST1*#*# --call 222-222-2222 #*#*TEST2*#*#</pre></code>

<p>Or, to get a similar effect from the opposite direction, the Test Runner could reduce the wait time
for the <code>many-numbers</code> test:</p>
<code><pre>tf >run many-numbers.xml --timeout 5000</code></pre>