Prime Number Generator Coding Exercise
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Overview
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Your task is to use test driven development to implement a prime number generator that
returns an ordered list of all prime numbers in a given range (inclusive of the endpoints).
You must implement the interface specified below. You may also create any other
methods, interfaces and/or classes that you deem necessary to complete the project.
You should also develop a small main program to drive your generator and to allow the
user to specify the prime number range via the command line. To successfully
complete the exercise, all unit tests must pass as well as provide 100% code coverage.
Notes:
• The code should handle inverse ranges such that 1-10 and 10-1 are equivalent.
• Ensure that you run a test against the range 7900 and 7920 (valid primes are 7901,
7907, 7919).
Interface:
Interface PrimeNumberGenerator {
List<Integer> generate(int startingValue, int endingValue);
boolean isPrime(int value);
}
Definition (from wikipedia):
In mathematics, a prime number (or a prime) is a natural number which has exactly
two distinct natural number divisors: 1 and itself. The first twenty-six prime numbers are:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89,
97, 101
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TESTING and REPORTING
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Test Report and Code Coverage can be generated with:
# gradlew test jacoco codenarcMain
Reports are available at:
build/reports/jacoco/test/html/index.html
build/reports/tests/index.html
build/reports/codenarc/main.html
Groovy adds some bits to the bytecode, so, the Instructions coverage won't be 100%. However branch
coverage is at 100%
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TO RUN THE PROJECT
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First build it:
# gradlew installDist; cd build/install/prime/bin
Then run:
On *nix or mac:
# ./prime --start 0 --end 1000
On Windows:
# prime.bat --start 0 --end 1000