1 Integration Tests - High-Level View

The Report Writers need to be tested. Since the Report Writers need to retrieve data from

• Website
• HTMLDocument
• Resource and its associated classes

and make use of various support libraries… the resulting tests are Integration Tests.

For the purpose of this discussion… we will use the following definitions:

• Unit Test - a test that examines a single class without involving other classes.

• Integration Test - a test that examines the interaction between two or more classes.

• System Test - a test the examines the program as a whole (start to finish).

  The line between integration and system tests is often fuzzy.

For Unit Test suites… the mutator-accessor strategy provides a framework for constructing a test…

1. Set up the object to be tested
2. Call the mutator function under evaluation
3. Call each accessor to confirm that:
   1. The expected change was made.
   2. No unexpected changes were made.

Integration tests require a different approach. Our steps will become something along the lines of…

1. Remember that if we are testing code that uses an existing library, either built-in (e.g., BufferedReader) or external (e.g., JSoup)…

   1. We are testing our code and how it uses the library.
   2. We are not testing the library itself.

2. Set up a small set of test data (i.e., small enough to check by hand).

3. Check the results of calling the library, not the library itself.

   This is a nuanced difference. Do not worry… there will be an example later in this discussion.

2 Testing the Report Writers

The Report Writers will be tested with Integration Tests.

2.1 Text Writer Test

Let us take a quick look of logic involved in testing the TextReportWriter.

@startuml test_sequence_03.svg
autoactivate on
hide footbox
skinparam backgroundColor #FFFFFF
skinparam sequenceParticipant underline

title Report Generation: Integeration Test Flow


participant ":TestTextReportWriter" as driver
activate driver

driver -> driver: setUp()
    create "site:Website" as site
    driver -> site: new()
    return
    driver -> site: [populate with "faked" pages]
    return
return

create ":StringWriter" as strWriter
driver -> strWriter: new()
return
create ":BufferedWriter" as bufWriter
driver -> bufWriter: new(strWriter)
return

create ":TextReportWriter" as textWriter
driver -> textWriter: new()
return
driver -> textWriter: setSourceData(site)
return
driver -> textWriter: setBaseName(...)
return
driver -> textWriter: write(bufWriter)
return
driver -> textWriter !!: delete

driver ->  strWriter: toString()
return resultStr

note right: [examine "resultStr" with Hamcrest String matchers]

@enduml

Take note of how a BufferWriter and a StringWriter were used to capture the output. This is a standard trick… and the reason why I emphasize the use of BufferedWriter and BufferedReader so heavily.

2.2 JSON Writer Test

Let us also take a quick look of logic involved in testing the JSONReportWriter.

@startuml test_sequence_04.svg
autoactivate on
hide footbox
skinparam backgroundColor #FFFFFF
skinparam sequenceParticipant underline

title Report Generation: Integeration Test Flow


participant ":TestJSONReportWriter" as driver
activate driver

driver -> driver: setUp()
    create "site:Website" as site
    driver -> site: new()
    return
    driver -> site: [populate with "faked" pages]
    return
return

create ":StringWriter" as strWriter
driver -> strWriter: new()
return
create ":BufferedWriter" as bufWriter
driver -> bufWriter: new(strWriter)
return

create ":JSONReportWriter" as jsonWriter
driver -> jsonWriter: new()
return
driver -> jsonWriter: setSourceData(site)
return
driver -> jsonWriter: setBaseName(...)
return
driver -> jsonWriter: write(bufWriter)
return
driver -> jsonWriter !!: delete

driver ->  strWriter: toString()
return resultStr

note right: [examine "resultStr" with Hamcrest String matchers]

@enduml

Do the steps seem familiar? In fact… they are near identical due to the fact that JSON is just formatted text data.

Now… what does the code entail? How do we approach these tests?