Clover

1
Clover

• http//www.cenqua.com/clover
• Commercial tool requires license
• Supports method, statement, and branch coverage
• Reports its findings in multiple formats
• From project level down to individual lines of
  source code
• Historical charting of code coverage and other
  metrics
• Plug-in versions available for Eclipse, NetBeans

2
Clover plugin for Eclipse
3
Clover coverage filters

• One can choose not to instrument certain types of
  blocks in the code (e.g. assertions and exception
  catching), in order to focus on the coverage of
  interest.

4
Emma

• Open-source tool
• Supports class, method, basic block, and line
  coverage.
• Fractional line coverage supported, but not
  branch coverage.
• Standalone version works with Ant builds
• http//emma.sourceforge.net
• Eclipse plugin EclEmma also available
• http//www.eclemma.org

5
Emma

• Uses bytecode instrumentation.
• Classes can be instrumented in advance, or during
  class loading.
• Tool keeps a metadata file to associate bytecode
  with source code
• A regular compile will allow for only limited
  metadata.
• A compile with debug option will provide more
  information to support branch coverage.

6
Block Coverage

• Block coverage assumes that if a block of
  statements without branches is entered and
  exited, all statements in the block were
  executed.
• That is, the counter is at the end of the block,
  instead of before the source code statement.
• Result If an exception occurs in the block, the
  entire block is not recorded as having executed.
• This may be fine for application source code, but
  it does not work well with JUnit test source
  code.
• JUnit throws exceptions internally when tests
  fail, so the test may not have appeared to be
  executed.

7
Emma coverage report
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Emma source code annotations
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Fractional line coverage
Only part of conditional executed
Loop increment not executed
10
Anomalies with byte code coverage

• There are cases where the compiler may emit
  multiple copies of object code for a single
  instance of source code.
• In the above example, there is an instance
  variable initialized for each of two
  constructors. However, only one constructor is
  called.

11
Coverlipse

• Open source Eclipse plug-in
• http//coverlipse.sourceforge.net
• Provides block coverage, all-uses data flow
  coverage
• No branch coverage
• Uses Apache BCEL to instrument bytecode

12
Line coverage report
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All-uses coverage report
14
All-uses coverage report
15
Cobertura

• Open source tool for Java code coverage
• http//cobertura.sourceforge.net
• Measures line coverage, branch coverage, and
  McCabe cyclomatic complexity metric for methods.
• Branch coverage requires compilation with debug
  option.
• Must be run as an Ant task, with four stages
• Compile source code
• Instrument classes
• Run code
• Generate report

16
Cobertura summary report
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Cobertura detail report
18
References

• Clover http//www.cenqua.com/clover
• Emma
• http//emma.sourceforge.net
• http//www.eclemma.org
• Coverlipse http//coverlipse.sourceforge.net
• Cobertura http//cobertura.sourceforge.net
• A. Glover, Dont be fooled by the Coverage
  Report, IBM developer works article
• http//www-128.ibm.com/developerworks/java/library
  /j-cq01316
• S. Gornett, Code Coverage Analysis
• http//www.bullseye.com/coverage.html