Update JUnit Test Classes and there dependencies

[HeinrichAD]

This PR looks still very huge. However, this is due to the exchange of the test framework. This PR is one part of #189.

File changes summary

pom.xml                                                             |  22 +--
src/main/java/net/sourceforge/plantuml/servlet/OldProxyServlet.java |  68 +++----
src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java    |   1 +
src/main/webapp/index.jsp                                           |   2 +-
src/test/java/net/sourceforge/plantuml/servlet/ServerUtils.java     |  38 ----
src/test/java/net/sourceforge/plantuml/servlet/TestAsciiArt.java    |  24 +--
src/test/java/net/sourceforge/plantuml/servlet/TestCharset.java     |  43 +++--
src/test/java/net/sourceforge/plantuml/servlet/TestCheck.java       |  40 ++--
src/test/java/net/sourceforge/plantuml/servlet/TestEPS.java         |  25 +--
src/test/java/net/sourceforge/plantuml/servlet/TestForm.java        | 294 ++++++++++++++++++------------
src/test/java/net/sourceforge/plantuml/servlet/TestImage.java       |  84 ++++-----
src/test/java/net/sourceforge/plantuml/servlet/TestLanguage.java    |  13 +-
src/test/java/net/sourceforge/plantuml/servlet/TestMap.java         |  80 +++++---
src/test/java/net/sourceforge/plantuml/servlet/TestOldProxy.java    |  84 ++++-----
src/test/java/net/sourceforge/plantuml/servlet/TestProxy.java       | 120 ++++++++----
src/test/java/net/sourceforge/plantuml/servlet/TestSVG.java         | 131 +++++++------
src/test/java/net/sourceforge/plantuml/servlet/TestUtils.java       |   6 +-
src/test/java/net/sourceforge/plantuml/servlet/WebappTestCase.java  |  81 +++++++-
18 files changed, 660 insertions(+), 496 deletions(-)

The first 4 files contain real changes. The test files themselfe should not contain important changes (framework switch).

Changes

• Test Server
  • It is now possible run the junit tests against an external plantuml-server. This could be used to also test the finished jetty und tomcat docker images. Note: ServerUtils.java moved to server/EmbeddedJettyServer.java
  • Open TODO: The embedded jetty server (before ServerUtils.java) uses jetty 8. Jetty 8 is deprecated and at least I have sometimes problems to get this version running on my system. Possible solutions
    • update to jetty 11
    • test against external server, e.g. docker-compose up (also see: WebappTestCase Constructor)
• JUnit Tests
  • Simplify tests by using java.net.URL instead of an (old) framework.
  • Enable JavaScript by default for a more realistic testing environment.
  • Some little fixes
• pom.xml
  • remove HTTPClient artifact HTTPClient was last updated in Nov, 2005 This was only used in OldProxyServlet.handleImageProxy()
  • switch from HttpUnit to HtmlUnit HttpUnit is an old framework which is nearly never updates
  • remove rhino:js Only necessary in combination with HttpUnit.
  • Make tests at least manually runable. Currently, test will be skipped by default. Add skipTests as property so that you can at least manually change it via:
  • mvn test -DskipTests=false
  • mvn test -DskipTests=false -DargLine="-Dsystem.test.server=http://localhost:8080/plantuml"