diff --git a/pom.xml b/pom.xml index da3084ab2..102668588 100644 --- a/pom.xml +++ b/pom.xml @@ -196,6 +196,7 @@ transaction-script filterer factory + separated-interface diff --git a/separated-interface/README.md b/separated-interface/README.md new file mode 100644 index 000000000..ca7a12e44 --- /dev/null +++ b/separated-interface/README.md @@ -0,0 +1,119 @@ +--- +layout: pattern +title: Separated Interface +folder: separated-interface +permalink: /patterns/separated-interface/ +categories: Structural +tags: + - Decoupling +--- + + +## Intent +Separate the interface definition and implementation in different packages. This allows the client to be completely unaware of the implementation. + +## Explanation + +Real world example + +> An Invoice generator may be created with ability to use different Tax calculators that may be added in the invoice depending upon type of purchase, region etc. + +In plain words + +> Separated interface pattern encourages to keep the implementations of an interface decoupled from the client and its definition, so the client is not dependent on the implementation. + +A client code may abstract some specific functionality to an interface, and define the definition of the interface as an SPI ([Service Programming Interface](https://en.wikipedia.org/wiki/Service_provider_interface) is an API intended and open to be implemented or extended by a third party). Another package may implement this interface definition with a concrete logic, which will be injected into the client code at runtime (with a third class, injecting the implementation in the client) or at compile time (using Plugin pattern with some configurable file). + +**Programmatic Example** + +**Client** An Invoice generator class accepts the cost of the product and calculates the total amount payable inclusive of tax + +```java +public class InvoiceGenerator { + + private final TaxCalculator taxCalculator; + + private final double amount; + + public InvoiceGenerator(double amount, TaxCalculator taxCalculator) { + this.amount = amount; + this.taxCalculator = taxCalculator; + } + + public double getAmountWithTax() { + return amount + taxCalculator.calculate(amount); + } + +} +``` +The tax calculation logic is delegated to the ```TaxCalculator``` interface + +```java + +public interface TaxCalculator { + + double calculate(double amount); + +} + +``` + +**Implementation package** +In another package (which the client is completely unaware of) there exist multiple implementations of the ```TaxCalculator``` interface +```ForeignTaxCalculator``` which levies 60% tax for international products. +```java +public class ForeignTaxCalculator implements TaxCalculator { + + public static final double TAX_PERCENTAGE = 60; + + @Override + public double calculate(double amount) { + return amount * TAX_PERCENTAGE / 100.0; + } + +} +``` + +```DomesticTaxCalculator``` which levies 20% tax for international products. +```java +public class DomesticTaxCalculator implements TaxCalculator { + + public static final double TAX_PERCENTAGE = 20; + + @Override + public double calculate(double amount) { + return amount * TAX_PERCENTAGE / 100.0; + } + +} +``` + +These both implementations are instantiated and injected in the client class by the ```App.java``` class + +```java + var internationalProductInvoice = new InvoiceGenerator(PRODUCT_COST, new ForeignTaxCalculator()); + + LOGGER.info("Foreign Tax applied: {}", "" + internationalProductInvoice.getAmountWithTax()); + + var domesticProductInvoice = new InvoiceGenerator(PRODUCT_COST, new DomesticTaxCalculator()); + + LOGGER.info("Domestic Tax applied: {}", "" + domesticProductInvoice.getAmountWithTax()); +``` + +## Class diagram +![alt text](./etc/class_diagram.png "Separated Interface") + +## Applicability +Use the Separated interface pattern when + +* You are developing a framework package, and your framework needs to call some application code through interfaces. +* You have separate packages implementing the functionalities which may be plugged in your client code at runtime or compile-time. +* Your code resides in a layer that is not allowed to call the interface implementation layer by rule. For example, a domain layer needs to call a data mapper. + +## Tutorial + +* [Separated Interface Tutorial](https://www.youtube.com/watch?v=d3k-hOA7k2Y) + +## Credits + +* [Martin Fowler](https://www.martinfowler.com/eaaCatalog/separatedInterface.html) diff --git a/separated-interface/etc/class_diagram.png b/separated-interface/etc/class_diagram.png new file mode 100644 index 000000000..10d509801 Binary files /dev/null and b/separated-interface/etc/class_diagram.png differ diff --git a/separated-interface/etc/separated-interface.urm.puml b/separated-interface/etc/separated-interface.urm.puml new file mode 100644 index 000000000..eab2ad60c --- /dev/null +++ b/separated-interface/etc/separated-interface.urm.puml @@ -0,0 +1,36 @@ +@startuml +package com.iluwatar.separatedinterface { + class App { + - LOGGER : Logger {static} + + PRODUCT_COST : double {static} + + App() + + main(args : String[]) {static} + } +} +package com.iluwatar.separatedinterface.taxes { + class DomesticTaxCalculator { + + TAX_PERCENTAGE : double {static} + + DomesticTaxCalculator() + + calculate(amount : double) : double + } + class ForeignTaxCalculator { + + TAX_PERCENTAGE : double {static} + + ForeignTaxCalculator() + + calculate(amount : double) : double + } +} +package com.iluwatar.separatedinterface.invoice { + class InvoiceGenerator { + - amount : double + - taxCalculator : TaxCalculator + + InvoiceGenerator(amount : double, taxCalculator : TaxCalculator) + + getAmountWithTax() : double + } + interface TaxCalculator { + + calculate(double) : double {abstract} + } +} +InvoiceGenerator --> "-taxCalculator" TaxCalculator +DomesticTaxCalculator ..|> TaxCalculator +ForeignTaxCalculator ..|> TaxCalculator +@enduml \ No newline at end of file diff --git a/separated-interface/pom.xml b/separated-interface/pom.xml new file mode 100644 index 000000000..da7584a93 --- /dev/null +++ b/separated-interface/pom.xml @@ -0,0 +1,71 @@ + + + + 4.0.0 + + com.iluwatar + java-design-patterns + 1.24.0-SNAPSHOT + + separated-interface + + + org.junit.jupiter + junit-jupiter-engine + test + + + org.junit.jupiter + junit-jupiter-params + test + + + org.mockito + mockito-core + test + + + + + + org.apache.maven.plugins + maven-assembly-plugin + + + + + + com.iluwatar.separatedinterface.App + + + + + + + + + diff --git a/separated-interface/src/main/java/com/iluwatar/separatedinterface/App.java b/separated-interface/src/main/java/com/iluwatar/separatedinterface/App.java new file mode 100644 index 000000000..1951e738b --- /dev/null +++ b/separated-interface/src/main/java/com/iluwatar/separatedinterface/App.java @@ -0,0 +1,62 @@ +/* + * The MIT License + * Copyright © 2014-2019 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.separatedinterface; + +import com.iluwatar.separatedinterface.invoice.InvoiceGenerator; +import com.iluwatar.separatedinterface.taxes.DomesticTaxCalculator; +import com.iluwatar.separatedinterface.taxes.ForeignTaxCalculator; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + *

The Separated Interface pattern encourages to separate the interface definition and + * implementation in different packages. This allows the client to be completely unaware of the + * implementation.

+ * + *

In this class the {@link InvoiceGenerator} class is injected with different instances of + * {@link com.iluwatar.separatedinterface.invoice.TaxCalculator} implementations located in separate + * packages, to receive different responses for both of the implementations.

+ */ +public class App { + + private static final Logger LOGGER = LoggerFactory.getLogger(App.class); + + public static final double PRODUCT_COST = 50.0; + + /** + * Program entry point. + * + * @param args command line args + */ + public static void main(String[] args) { + //Create the invoice generator with product cost as 50 and foreign product tax + var internationalProductInvoice = new InvoiceGenerator(PRODUCT_COST, + new ForeignTaxCalculator()); + LOGGER.info("Foreign Tax applied: {}", "" + internationalProductInvoice.getAmountWithTax()); + + //Create the invoice generator with product cost as 50 and domestic product tax + var domesticProductInvoice = new InvoiceGenerator(PRODUCT_COST, new DomesticTaxCalculator()); + LOGGER.info("Domestic Tax applied: {}", "" + domesticProductInvoice.getAmountWithTax()); + } +} diff --git a/separated-interface/src/main/java/com/iluwatar/separatedinterface/invoice/InvoiceGenerator.java b/separated-interface/src/main/java/com/iluwatar/separatedinterface/invoice/InvoiceGenerator.java new file mode 100644 index 000000000..c17ed5ac5 --- /dev/null +++ b/separated-interface/src/main/java/com/iluwatar/separatedinterface/invoice/InvoiceGenerator.java @@ -0,0 +1,51 @@ +/* + * The MIT License + * Copyright © 2014-2019 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.separatedinterface.invoice; + +/** + * InvoiceGenerator class generates an invoice, accepting the product cost and calculating the total + * price payable inclusive tax (calculated by {@link TaxCalculator}). + */ +public class InvoiceGenerator { + + /** + * The TaxCalculator interface to calculate the payable tax. + */ + private final TaxCalculator taxCalculator; + + /** + * The base product amount without tax. + */ + private final double amount; + + public InvoiceGenerator(double amount, TaxCalculator taxCalculator) { + this.amount = amount; + this.taxCalculator = taxCalculator; + } + + public double getAmountWithTax() { + return amount + taxCalculator.calculate(amount); + } + +} \ No newline at end of file diff --git a/separated-interface/src/main/java/com/iluwatar/separatedinterface/invoice/TaxCalculator.java b/separated-interface/src/main/java/com/iluwatar/separatedinterface/invoice/TaxCalculator.java new file mode 100644 index 000000000..aa4b81a84 --- /dev/null +++ b/separated-interface/src/main/java/com/iluwatar/separatedinterface/invoice/TaxCalculator.java @@ -0,0 +1,30 @@ +/* + * The MIT License + * Copyright © 2014-2019 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.separatedinterface.invoice; + +public interface TaxCalculator { + + double calculate(double amount); + +} diff --git a/separated-interface/src/main/java/com/iluwatar/separatedinterface/taxes/DomesticTaxCalculator.java b/separated-interface/src/main/java/com/iluwatar/separatedinterface/taxes/DomesticTaxCalculator.java new file mode 100644 index 000000000..788afb90a --- /dev/null +++ b/separated-interface/src/main/java/com/iluwatar/separatedinterface/taxes/DomesticTaxCalculator.java @@ -0,0 +1,40 @@ +/* + * The MIT License + * Copyright © 2014-2019 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.separatedinterface.taxes; + +import com.iluwatar.separatedinterface.invoice.TaxCalculator; + +/** + * TaxCalculator for Domestic goods with 20% tax. + */ +public class DomesticTaxCalculator implements TaxCalculator { + + public static final double TAX_PERCENTAGE = 20; + + @Override + public double calculate(double amount) { + return amount * TAX_PERCENTAGE / 100.0; + } + +} diff --git a/separated-interface/src/main/java/com/iluwatar/separatedinterface/taxes/ForeignTaxCalculator.java b/separated-interface/src/main/java/com/iluwatar/separatedinterface/taxes/ForeignTaxCalculator.java new file mode 100644 index 000000000..c2b12e2f5 --- /dev/null +++ b/separated-interface/src/main/java/com/iluwatar/separatedinterface/taxes/ForeignTaxCalculator.java @@ -0,0 +1,40 @@ +/* + * The MIT License + * Copyright © 2014-2019 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.separatedinterface.taxes; + +import com.iluwatar.separatedinterface.invoice.TaxCalculator; + +/** + * TaxCalculator for foreign goods with 60% tax. + */ +public class ForeignTaxCalculator implements TaxCalculator { + + public static final double TAX_PERCENTAGE = 60; + + @Override + public double calculate(double amount) { + return amount * TAX_PERCENTAGE / 100.0; + } + +} diff --git a/separated-interface/src/test/java/com/iluwatar/separatedinterface/AppTest.java b/separated-interface/src/test/java/com/iluwatar/separatedinterface/AppTest.java new file mode 100644 index 000000000..4114f9bb7 --- /dev/null +++ b/separated-interface/src/test/java/com/iluwatar/separatedinterface/AppTest.java @@ -0,0 +1,41 @@ +/* + * The MIT License + * Copyright © 2014-2019 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.separatedinterface; + +import org.junit.jupiter.api.Test; + +import com.iluwatar.separatedinterface.App; + +import static org.junit.jupiter.api.Assertions.assertDoesNotThrow; + +/** + * Application test. + */ +class AppTest { + + @Test + void shouldExecuteWithoutException() { + assertDoesNotThrow(() -> App.main(new String[]{})); + } +} diff --git a/separated-interface/src/test/java/com/iluwatar/separatedinterface/invoice/InvoiceGeneratorTest.java b/separated-interface/src/test/java/com/iluwatar/separatedinterface/invoice/InvoiceGeneratorTest.java new file mode 100644 index 000000000..ac75d3b70 --- /dev/null +++ b/separated-interface/src/test/java/com/iluwatar/separatedinterface/invoice/InvoiceGeneratorTest.java @@ -0,0 +1,48 @@ +/* + * The MIT License + * Copyright © 2014-2019 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.separatedinterface.invoice; + +import org.junit.jupiter.api.Assertions; +import org.junit.jupiter.api.Test; + +import static org.mockito.Mockito.*; + +public class InvoiceGeneratorTest { + + private InvoiceGenerator target; + + @Test + public void testGenerateTax() { + var productCost = 50.0; + var tax = 10.0; + TaxCalculator taxCalculatorMock = mock(TaxCalculator.class); + doReturn(tax).when(taxCalculatorMock).calculate(productCost); + + target = new InvoiceGenerator(productCost, taxCalculatorMock); + + Assertions.assertEquals(target.getAmountWithTax(), productCost + tax); + verify(taxCalculatorMock, times(1)).calculate(productCost); + } + +} diff --git a/separated-interface/src/test/java/com/iluwatar/separatedinterface/taxes/DomesticTaxCalculatorTest.java b/separated-interface/src/test/java/com/iluwatar/separatedinterface/taxes/DomesticTaxCalculatorTest.java new file mode 100644 index 000000000..dac3ec2d6 --- /dev/null +++ b/separated-interface/src/test/java/com/iluwatar/separatedinterface/taxes/DomesticTaxCalculatorTest.java @@ -0,0 +1,41 @@ +/* + * The MIT License + * Copyright © 2014-2019 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.separatedinterface.taxes; + +import org.junit.jupiter.api.Assertions; +import org.junit.jupiter.api.Test; + +public class DomesticTaxCalculatorTest { + + private DomesticTaxCalculator target; + + @Test + public void testTaxCalculation(){ + target = new DomesticTaxCalculator(); + + var tax=target.calculate(100.0); + Assertions.assertEquals(tax,20.0); + } + +} diff --git a/separated-interface/src/test/java/com/iluwatar/separatedinterface/taxes/ForeignTaxCalculatorTest.java b/separated-interface/src/test/java/com/iluwatar/separatedinterface/taxes/ForeignTaxCalculatorTest.java new file mode 100644 index 000000000..22526b6df --- /dev/null +++ b/separated-interface/src/test/java/com/iluwatar/separatedinterface/taxes/ForeignTaxCalculatorTest.java @@ -0,0 +1,41 @@ +/* + * The MIT License + * Copyright © 2014-2019 Ilkka Seppälä + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +package com.iluwatar.separatedinterface.taxes; + +import org.junit.jupiter.api.Assertions; +import org.junit.jupiter.api.Test; + +public class ForeignTaxCalculatorTest { + + private ForeignTaxCalculator target; + + @Test + public void testTaxCalculation(){ + target = new ForeignTaxCalculator(); + + var tax=target.calculate(100.0); + Assertions.assertEquals(tax,60.0); + } + +}