Tax service implementation + tests

pom.xml

@@ -11,6 +11,8 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven-compiler-plugin.version>3.8.0</maven-compiler-plugin.version>
+        <maven-surefire-plugin.version>2.22.0</maven-surefire-plugin.version>
+        <junit.version>5.3.2</junit.version>
     </properties>
 
     <build>
@@ -23,6 +25,31 @@
                     <release>11</release>
                 </configuration>
             </plugin>
+            <plugin>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>${maven-surefire-plugin.version}</version>
+            </plugin>
         </plugins>
     </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-params</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
 </project>

src/main/java/com/aa/gitbisect/service/TaxCalculationService.java

@@ -1,10 +1,20 @@
 package com.aa.gitbisect.service;
 
 import java.math.BigDecimal;
+import java.math.RoundingMode;
 
 public class TaxCalculationService {
 
+    private static final BigDecimal HUNDRED = BigDecimal.valueOf(100);
+    private static final RoundingMode ROUNDING_MODE = RoundingMode.HALF_UP;
+
     public BigDecimal getNetSalaryInCurrency(BigDecimal grossSalaryInCurrency, int taxInPercent) {
-        return null;
+        BigDecimal taxInCurrency = grossSalaryInCurrency
+                .multiply(BigDecimal.valueOf(taxInPercent))
+                .divide(HUNDRED, ROUNDING_MODE);
+
+        return grossSalaryInCurrency
+                .subtract(taxInCurrency)
+                .setScale(2, ROUNDING_MODE);
     }
 }

src/test/java/com/aa/gitbisect/service/TaxCalculationServiceTest.java

@@ -0,0 +1,28 @@
+package com.aa.gitbisect.service;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import java.math.BigDecimal;
+
+public class TaxCalculationServiceTest {
+
+    private TaxCalculationService taxCalculationService = new TaxCalculationService();
+
+    @ParameterizedTest
+    @CsvSource({
+            "100.00, 10, 90.00",
+            "100.00, 3, 97.00",
+            "123.45, 5, 117.28"
+
+    })
+    public void testNetSalaryCalculation(
+            BigDecimal grossSalaryInCurrency, int taxInPercent, BigDecimal expectedNetSalaryInCurrency) {
+
+        BigDecimal actualNetSalaryInCurrency =
+                taxCalculationService.getNetSalaryInCurrency(grossSalaryInCurrency, taxInPercent);
+
+        Assertions.assertEquals(expectedNetSalaryInCurrency, actualNetSalaryInCurrency);
+    }
+}