Hello coders, today we are going to solve Day 27: Testing HackerRank Solution in C++, Java and Python.
Task
This problem is about unit testing.
Your company needs a function that meets the following requirements:
- For a given array of n integers, the function returns the index of the element with the minimum value in the array. If there is more than one element with the minimum value, it returns the smallest one.
- If an empty array is passed to the function, it raises an exception. A colleague has written this method. The implementation in Python is listed below. Implementations in other languages can be found in the code template.
def minimum_index(seq):
if len(seq) == 0:
raise ValueError("Cannot get the minimum value index from an empty sequence")
min_idx = 0
for i in range(1, len(seq)):
if a[i] < a[min_idx]:
min_idx = i
return min_idxA coworker has prepared functions that will perform the tests and validate return values. Finish the implementation of classes to provide data and expected results for the tests.
Complete the following methods.
In the class TestDataEmptyArray:
get_array()returns an empty array
In the class TestDataUniqueValues:
get_array()returns an array of size at least 2 with all unique elementsget_expected_result()returns the expected minimum value index for this array
In the class TestDataExactlyTwoDifferentMinimums:
get_array()returns an array where the minimum value occurs at exactly 2 indicesget_expected_result()returns the expected index
Take a look at the code template to see the exact implementation of functions that your colleague already implemented.
Note: The arrays are indexed from 0.
Solution – Day 27: Testing
Java
import java.util.*;
public class Solution {
public static int minimum_index(int[] seq) {
if (seq.length == 0) {
throw new IllegalArgumentException("Cannot get the minimum value index from an empty sequence");
}
int min_idx = 0;
for (int i = 1; i < seq.length; ++i) {
if (seq[i] < seq[min_idx]) {
min_idx = i;
}
}
return min_idx;
}
static class TestDataEmptyArray {
public static int[] get_array() {
int arr[]={};
return arr;
}
}
static class TestDataUniqueValues {
public static int[] get_array() {
// complete this function
int arr[]={1,2,3,4,5};
return arr;
}
public static int get_expected_result() {
// complete this function
return 0;
}
}
static class TestDataExactlyTwoDifferentMinimums {
public static int[] get_array() {
// complete this function
int arr[]={1,3,1};
return arr;
}
public static int get_expected_result() {
// complete this function
return 0;
}
}
public static void TestWithEmptyArray() {
try {
int[] seq = TestDataEmptyArray.get_array();
int result = minimum_index(seq);
} catch (IllegalArgumentException e) {
return;
}
throw new AssertionError("Exception wasn't thrown as expected");
}
public static void TestWithUniqueValues() {
int[] seq = TestDataUniqueValues.get_array();
if (seq.length < 2) {
throw new AssertionError("less than 2 elements in the array");
}
Integer[] tmp = new Integer[seq.length];
for (int i = 0; i < seq.length; ++i) {
tmp[i] = Integer.valueOf(seq[i]);
}
if (!((new LinkedHashSet<Integer>(Arrays.asList(tmp))).size() == seq.length)) {
throw new AssertionError("not all values are unique");
}
int expected_result = TestDataUniqueValues.get_expected_result();
int result = minimum_index(seq);
if (result != expected_result) {
throw new AssertionError("result is different than the expected result");
}
}
public static void TestWithExactlyTwoDifferentMinimums() {
int[] seq = TestDataExactlyTwoDifferentMinimums.get_array();
if (seq.length < 2) {
throw new AssertionError("less than 2 elements in the array");
}
int[] tmp = seq.clone();
Arrays.sort(tmp);
if (!(tmp[0] == tmp[1] && (tmp.length == 2 || tmp[1] < tmp[2]))) {
throw new AssertionError("there are not exactly two minimums in the array");
}
int expected_result = TestDataExactlyTwoDifferentMinimums.get_expected_result();
int result = minimum_index(seq);
if (result != expected_result) {
throw new AssertionError("result is different than the expected result");
}
}
public static void main(String[] args) {
TestWithEmptyArray();
TestWithUniqueValues();
TestWithExactlyTwoDifferentMinimums();
System.out.println("OK");
}
}
Python
def minimum_index(seq):
if len(seq) == 0:
raise ValueError("Cannot get the minimum value index from an empty sequence")
min_idx = 0
for i in range(1, len(seq)):
if seq[i] < seq[min_idx]:
min_idx = i
return min_idx
class TestDataEmptyArray(object):
@staticmethod
def get_array():
return []
# complete this function
class TestDataUniqueValues(object):
data = []
for i in range(5):
data.append(i)
data[::-1]
@staticmethod
def get_array():
return TestDataUniqueValues.data
@staticmethod
def get_expected_result():
data = TestDataUniqueValues.get_array()
return data.index(min(data))
# complete this function
class TestDataExactlyTwoDifferentMinimums(object):
data = []
for i in range(5):
data.append(i)
data[::-1]
data.insert(0,0)
@staticmethod
def get_array():
return TestDataExactlyTwoDifferentMinimums.data
@staticmethod
def get_expected_result():
data = TestDataExactlyTwoDifferentMinimums.get_array()
return data.index(min(data))
# complete this function
def TestWithEmptyArray():
try:
seq = TestDataEmptyArray.get_array()
result = minimum_index(seq)
except ValueError as e:
pass
else:
assert False
def TestWithUniqueValues():
seq = TestDataUniqueValues.get_array()
assert len(seq) >= 2
assert len(list(set(seq))) == len(seq)
expected_result = TestDataUniqueValues.get_expected_result()
result = minimum_index(seq)
assert result == expected_result
def TestiWithExactyTwoDifferentMinimums():
seq = TestDataExactlyTwoDifferentMinimums.get_array()
assert len(seq) >= 2
tmp = sorted(seq)
assert tmp[0] == tmp[1] and (len(tmp) == 2 or tmp[1] < tmp[2])
expected_result = TestDataExactlyTwoDifferentMinimums.get_expected_result()
result = minimum_index(seq)
assert result == expected_result
TestWithEmptyArray()
TestWithUniqueValues()
TestiWithExactyTwoDifferentMinimums()
print("OK")
Disclaimer: The above Problem (Day 27: Testing) is generated by Hacker Rank but the Solution is Provided by CodingBroz. This tutorial is only for Educational and Learning Purpose.