Extension Step storeDigest
Description
Stores a digest value for the response (or part of the response) into a property. This is useful when you don't care what the value within a response is but you want to ensure that the generated content hasn't changed. If any single character in the response changes, so will the digest. Supports content filters such as lineSeparatorFilter and replaceFilter to allow you to filter out changes that you don't care about and the table locator step if you are interested in content within a table.
Parameters
- property
- Required? yes
- The target property name.
- description
- Required? no
- The description of this test step.
- htmlId
- Required? no
- The id of an HTML element. If present, processing will be limited to this element. Will be ignored if a nested table step is used.
- propertyType
- Required? no, default is the "defaultPropertyType" as specified in the "config" element is used.
- The target property type. Either "ant" or "dynamic".
- type
- Required? no, default is SHA-1
- The type of message digest algorithm to use, e.g. 'MD5' or 'SHA-1'.
- xpath
- Required? no
- An XPath expression identifying an HTML element. If present, processing will be limited to this element. Will be ignored if htmlId is set or if a nested table step is used.
Nested Parameters
- step
- Required? yes
- A webtest step.
- table
- Required? no
- To locate a specific cell in a specific table on the page.
Details
The following example illustrates how to use the storeDigest step (illustrating the use of the nested line separator content filter which ensures that differences in line separator which may occur in different environments don't influence the digest value):
<property name="variableNumberRegex" value="(?<= )[0-9]+(?= time)"/>
<property name="visitCountDigest" value="c1 e2 29 ad d4 6b 2a 96 2f 18 18 f4 71 e6 bb 88 73 9a c7 62"/>
<webtest name="storeDigest: Show how to use storeDigest step">
<config ... />
<steps>
<invoke url="dummy.html"/>
<storeDigest property="dummyDigestSHA1">
<lineSeparatorFilter/>
</storeDigest>
<verifyProperty name="dummyDigestSHA1" text="4e 7e c7 59 21 9 15 44 52 f3 45 70 76 b9 a1 93 e7 b3 78 f2"/>
<storeDigest property="dummyDigestMD5" type="MD5">
<lineSeparatorFilter/>
</storeDigest>
<verifyProperty name="dummyDigestMD5" text="27 e2 37 6c ff d6 ac 13 65 8d 80 d9 94 0 f7 21"/>
</steps>
</webtest>
</target>
Note that both SHA-1 (the default) and MD5 digest are shown. These are the most commonly used digests with Java (because they are built in) but about 20 different kinds of digests are available in various cryptography packages for Java and may be available to you if someone has downloaded an appropriate class library and configured your systems to use it. You may also have heard of the related terms checksum and/or hash (sometimes loosely means a digest, sometimes meaning a weaker algorithm which can be used to detect some forms of content change) or digital signature (a digest value can be part of this).
At the moment the best way to calculate the digest value (so that you can write the test) is to use a dummy value (e.g. 'xxxxx') and then run the test. Then when it fails it will tell you what it was expecting. Simply copy that value into your test. Eventually we may store digest values in a file and populate the file for you the first time the test is run or we may have a tool (e.g. Mozilla plug-in or one of the other recorder tools) to pre-calculate digest values for you.
See also: the verifyContent, storeLength, lineSeparatorFilter, replaceFilter, tagStripper and contentStripper steps.