Name:
PID: (page 1)
public class HandlerTests {
@Test
public void handleRequest1() throws Exception {
DoubleHandler h = new DoubleHandler();
String url = "http://localhost:8080/double?num=1";
URI input = new URI(url);
String expected = "Doubling 1 produces 2.";
assertEquals(expected, h.handleRequest(input));
}
@Test
public void handleRequest2() throws Exception {
DoubleHandler h = new DoubleHandler();
String url = "http://localhost:8080/double?num=2";
URI input = new URI(url);
String expected = "Doubling 2 produces 4.";
assertEquals(expected, h.handleRequest(input));
}
}
local$ javac -cp .:lib/hamcrest-core-1.3.jar:lib/junit-4.13.2.jar *.java
local$ java -cp .:lib/hamcrest-core-1.3.jar:lib/junit-4.13.2.jar org.junit.runner.JUnitCore HandlerTests
g.junit.runner.JUnitCore HandlerTests
JUnit version 4.13.2
.E.
Time: 0.012
There was 1 failure:
1) handleRequest1(HandlerTests)
org.junit.ComparisonFailure: expected:<Doubling 1 produces [2].> but was:<Doubling 1 produces [3].>
at org.junit.Assert.assertEquals(Assert.java:117)
at org.junit.Assert.assertEquals(Assert.java:146)
at HandlerTests.handleRequest1(HandlerTests.java:13)
FAILURES!!!
Tests run: 2, Failures: 1
Which tests passed? Which failed?
What other tests would be important to write? Any way to structure the choice of tests?
How could we make writing future tests easier?
class DoubleHandler implements URLHandler {
String template = "Doubling %d produces %d.";
public String handleRequest(URI url) {
if (url.getPath().equals("/double")) {
String[] params = url.getQuery().split("=");
if (params[0].equals("num")) {
int num = Integer.parseInt(params[1]);
int doubl = num + 2;
return String.format(template, num, doubl);
}
}
return "404 Not Found!";
}
}
What would we do to take the file that defines DoubleHandler and create a Java program that starts a server using that handler?
Name:
PID: (page 2)
// Problem statement: write and test a method median that takes a double[] and produces the
// median number in that array.
Input Expected output
{ 4.0, 5.0, 6.0 } 5.0
// Consider the following implementations of median:
double medianA(double[] nums) {
return nums[nums.length / 2];
}
double medianB(double[] nums) {
int len = nums.length;
if(len % 2 == 1) { return nums[len / 2]; }
else { return (nums[len / 2] + nums[len / 2 + 1]) / 2;
}
double medianC(double[] nums) {
double total = 0;
for(double d: nums) {
total += d;
}
return total / nums.length;
}
double medianD(double[] nums) {
// make a copy to avoid sorting over the old copy
double[] cloned = nums.clone();
Arrays.sort(cloned);
return nums[cloned.length / 2];
}
Examples inspired by Wrenn and Krishnamurthi https://cs.brown.edu/~sk/Publications/Papers/Published/wk-examplar/