Fine tuning the batch APIs and minor adjustments

fineract-provider/src/test/java/org/apache/fineract/batch/command/CommandStrategyProviderTest.java

@@ -0,0 +1,134 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.batch.command;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.util.stream.Stream;
+import javax.ws.rs.HttpMethod;
+import org.apache.fineract.batch.command.internal.ActivateClientCommandStrategy;
+import org.apache.fineract.batch.command.internal.ApplyLoanCommandStrategy;
+import org.apache.fineract.batch.command.internal.ApplySavingsCommandStrategy;
+import org.apache.fineract.batch.command.internal.ApproveLoanCommandStrategy;
+import org.apache.fineract.batch.command.internal.ApproveLoanRescheduleCommandStrategy;
+import org.apache.fineract.batch.command.internal.CollectChargesCommandStrategy;
+import org.apache.fineract.batch.command.internal.CreateChargeCommandStrategy;
+import org.apache.fineract.batch.command.internal.CreateClientCommandStrategy;
+import org.apache.fineract.batch.command.internal.DisburseLoanCommandStrategy;
+import org.apache.fineract.batch.command.internal.GetLoanByIdCommandStrategy;
+import org.apache.fineract.batch.command.internal.GetTransactionByIdCommandStrategy;
+import org.apache.fineract.batch.command.internal.RepayLoanCommandStrategy;
+import org.apache.fineract.batch.command.internal.UnknownCommandStrategy;
+import org.apache.fineract.batch.command.internal.UpdateClientCommandStrategy;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.springframework.context.ApplicationContext;
+
+/**
+ * Tests {@link CommandStrategyProvider}.
+ */
+public class CommandStrategyProviderTest {
+
+    /**
+     * Command strategy provider.
+     *
+     * @return the test data stream
+     */
+    private static Stream<Arguments> provideCommandStrategies() {
+        return Stream.of(Arguments.of("clients", HttpMethod.POST, "createClientCommandStrategy", mock(CreateClientCommandStrategy.class)),
+                Arguments.of("clients/123", HttpMethod.PUT, "updateClientCommandStrategy", mock(UpdateClientCommandStrategy.class)),
+                Arguments.of("loans", HttpMethod.POST, "applyLoanCommandStrategy", mock(ApplyLoanCommandStrategy.class)),
+                Arguments.of("loans/123", HttpMethod.GET, "getLoanByIdCommandStrategy", mock(GetLoanByIdCommandStrategy.class)),
+                Arguments.of("loans/123?associations=all", HttpMethod.GET, "getLoanByIdCommandStrategy",
+                        mock(GetLoanByIdCommandStrategy.class)),
+                Arguments.of("loans/123?associations=all&exclude=guarantors", HttpMethod.GET, "getLoanByIdCommandStrategy",
+                        mock(GetLoanByIdCommandStrategy.class)),
+                Arguments.of("savingsaccounts", HttpMethod.POST, "applySavingsCommandStrategy", mock(ApplySavingsCommandStrategy.class)),
+                Arguments.of("loans/123/charges", HttpMethod.POST, "createChargeCommandStrategy", mock(CreateChargeCommandStrategy.class)),
+                Arguments.of("loans/123/charges", HttpMethod.GET, "collectChargesCommandStrategy",
+                        mock(CollectChargesCommandStrategy.class)),
+                Arguments.of("loans/123/transactions?command=repayment", HttpMethod.POST, "repayLoanCommandStrategy",
+                        mock(RepayLoanCommandStrategy.class)),
+                Arguments.of("clients/456?command=activate", HttpMethod.POST, "activateClientCommandStrategy",
+                        mock(ActivateClientCommandStrategy.class)),
+                Arguments.of("loans/123?command=approve", HttpMethod.POST, "approveLoanCommandStrategy",
+                        mock(ApproveLoanCommandStrategy.class)),
+                Arguments.of("loans/123?command=disburse", HttpMethod.POST, "disburseLoanCommandStrategy",
+                        mock(DisburseLoanCommandStrategy.class)),
+                Arguments.of("rescheduleloans/123?command=approve", HttpMethod.POST, "approveLoanRescheduleCommandStrategy",
+                        mock(ApproveLoanRescheduleCommandStrategy.class)),
+                Arguments.of("loans/123/transactions/123", HttpMethod.GET, "getTransactionByIdCommandStrategy",
+                        mock(GetTransactionByIdCommandStrategy.class)));
+    }
+
+    /**
+     * Tests {@link CommandStrategyProvider#getCommandStrategy} for success scenarios.
+     *
+     * @param url
+     *            the resource URL
+     * @param httpMethod
+     *            the resource HTTP method
+     * @param beanName
+     *            the context bean name
+     * @param commandStrategy
+     *            the command strategy
+     */
+    @ParameterizedTest
+    @MethodSource("provideCommandStrategies")
+    public void testGetCommandStrategySuccess(final String url, final String httpMethod, final String beanName,
+            final CommandStrategy commandStrategy) {
+        final ApplicationContext applicationContext = mock(ApplicationContext.class);
+        final CommandStrategyProvider commandStrategyProvider = new CommandStrategyProvider(applicationContext);
+        when(applicationContext.getBean(beanName)).thenReturn(commandStrategy);
+
+        final CommandStrategy result = commandStrategyProvider.getCommandStrategy(CommandContext.resource(url).method(httpMethod).build());
+        assertEquals(commandStrategy, result);
+    }
+
+    /**
+     * Command strategy provider for error scenarioss.
+     *
+     * @return the test data stream
+     */
+    private static Stream<Arguments> provideCommandStrategyResourceDetailsForErrors() {
+        return Stream.of(Arguments.of("loans/123?command=reject", HttpMethod.POST),
+                Arguments.of("loans/glimAccount/746?command=approve", HttpMethod.POST), Arguments.of("loans/123", HttpMethod.PUT));
+    }
+
+    /**
+     * Tests {@link CommandStrategyProvider#getCommandStrategy} for error scenarios.
+     *
+     * @param url
+     *            the resource URL
+     * @param httpMethod
+     *            the resource HTTP method
+     */
+    @ParameterizedTest
+    @MethodSource("provideCommandStrategyResourceDetailsForErrors")
+    public void testGetCommandStrategyForError(final String url, final String httpMethod) {
+        final ApplicationContext applicationContext = mock(ApplicationContext.class);
+        final CommandStrategyProvider commandStrategyProvider = new CommandStrategyProvider(applicationContext);
+
+        final CommandStrategy result = commandStrategyProvider.getCommandStrategy(CommandContext.resource(url).method(httpMethod).build());
+        assertEquals(UnknownCommandStrategy.class, result.getClass());
+    }
+}

fineract-provider/src/test/java/org/apache/fineract/batch/command/internal/GetLoanByIdCommandStrategyTest.java

@@ -0,0 +1,186 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.batch.command.internal;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.verify;
+
+import java.util.stream.Stream;
+import javax.ws.rs.HttpMethod;
+import javax.ws.rs.core.UriInfo;
+import org.apache.commons.lang3.RandomStringUtils;
+import org.apache.fineract.batch.domain.BatchRequest;
+import org.apache.fineract.batch.domain.BatchResponse;
+import org.apache.fineract.infrastructure.core.api.MutableUriInfo;
+import org.apache.fineract.portfolio.loanaccount.api.LoansApiResource;
+import org.apache.fineract.portfolio.loanaccount.exception.LoanNotFoundException;
+import org.apache.http.HttpStatus;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Captor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+public class GetLoanByIdCommandStrategyTest {
+
+    private static Stream<Arguments> provideQueryParameters() {
+        return Stream.of(Arguments.of(null, 0), Arguments.of("associations=all", 1),
+                Arguments.of("fields=id,principal,annualInterestRate&associations=repaymentSchedule,transactions", 2));
+    }
+
+    /**
+     * Test {@link GetLoanByIdCommandStrategy#execute} happy path scenario.
+     *
+     */
+    @ParameterizedTest
+    @MethodSource("provideQueryParameters")
+    public void testExecuteSuccessScenario(final String queryParameter, final int noOfQueryParams) {
+        // given
+        final TestContext testContext = new TestContext();
+
+        final Long loanId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final BatchRequest request = getBatchRequest(loanId, queryParameter);
+        final String responseBody = "{\\\"id\\\":2,\\\"accountNo\\\":\\\"000000002\\\"}";
+
+        given(testContext.loansApiResource.retrieveLoan(eq(loanId), eq(false), any(UriInfo.class))).willReturn(responseBody);
+
+        // when
+        final BatchResponse response = testContext.underTest.execute(request, testContext.uriInfo);
+
+        // then
+        assertThat(response.getStatusCode()).isEqualTo(HttpStatus.SC_OK);
+        assertThat(response.getRequestId()).isEqualTo(request.getRequestId());
+        assertThat(response.getHeaders()).isEqualTo(request.getHeaders());
+        assertThat(response.getBody()).isEqualTo(responseBody);
+
+        verify(testContext.loansApiResource).retrieveLoan(eq(loanId), eq(false), testContext.uriInfoCaptor.capture());
+        MutableUriInfo mutableUriInfo = testContext.uriInfoCaptor.getValue();
+        assertThat(mutableUriInfo.getAdditionalQueryParameters()).hasSize(noOfQueryParams);
+    }
+
+    /**
+     * Test {@link GetLoanByIdCommandStrategy#execute} for internal server error.
+     */
+    @Test
+    public void testExecuteForInternalServerError() {
+        // given
+        final TestContext testContext = new TestContext();
+        final Long loanId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final BatchRequest request = getBatchRequest(loanId, null);
+
+        given(testContext.loansApiResource.retrieveLoan(eq(loanId), eq(false), any(UriInfo.class)))
+                .willThrow(new RuntimeException("Some error"));
+
+        // when
+        final BatchResponse response = testContext.underTest.execute(request, testContext.uriInfo);
+
+        // then
+        assertThat(response.getStatusCode()).isEqualTo(HttpStatus.SC_INTERNAL_SERVER_ERROR);
+        assertThat(response.getBody()).isEqualTo("{\"Exception\": java.lang.RuntimeException: Some error}");
+        assertThat(response.getRequestId()).isEqualTo(request.getRequestId());
+        assertThat(response.getHeaders()).isEqualTo(request.getHeaders());
+    }
+
+    /**
+     * Test {@link GetLoanByIdCommandStrategy#execute} for loan not found exception.
+     */
+    @Test
+    public void testExecuteForLoanNotFoundException() {
+        // given
+        final TestContext testContext = new TestContext();
+        final Long loanId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final BatchRequest request = getBatchRequest(loanId, null);
+
+        given(testContext.loansApiResource.retrieveLoan(eq(loanId), eq(false), any(UriInfo.class)))
+                .willThrow(new LoanNotFoundException(loanId));
+
+        // when
+        final BatchResponse response = testContext.underTest.execute(request, testContext.uriInfo);
+
+        // then
+        assertThat(response.getStatusCode()).isEqualTo(HttpStatus.SC_NOT_FOUND);
+        assertThat(response.getBody()).isEqualTo(buildLoanNotFoundError(loanId));
+        assertThat(response.getRequestId()).isEqualTo(request.getRequestId());
+        assertThat(response.getHeaders()).isEqualTo(request.getHeaders());
+    }
+
+    private String buildLoanNotFoundError(final Long loanId) {
+        return String.format(
+                "{\n  \"developerMessage\": \"The requested resource is not available.\",\n"
+                        + "  \"httpStatusCode\": \"404\",\n  \"defaultUserMessage\": \"The requested resource is not available.\",\n"
+                        + "  \"userMessageGlobalisationCode\": \"error.msg.resource.not.found\",\n  \"errors\": [\n    {\n"
+                        + "      \"developerMessage\": \"Loan with identifier %s does not exist\",\n"
+                        + "      \"defaultUserMessage\": \"Loan with identifier %s does not exist\",\n"
+                        + "      \"userMessageGlobalisationCode\": \"error.msg.loan.id.invalid\",\n      \"parameterName\": \"id\",\n"
+                        + "      \"args\": [\n        {\n          \"value\": %s\n        }\n      ]\n    }\n  ]\n" + "}",
+                loanId, loanId, loanId);
+    }
+
+    /**
+     * Creates and returns a request with the given loan id.
+     *
+     * @param loanId
+     *            the loan id
+     * @return BatchRequest
+     */
+    private BatchRequest getBatchRequest(final Long loanId, final String queryParamStr) {
+
+        final BatchRequest br = new BatchRequest();
+        String relativeUrl = "loans/" + loanId;
+        if (queryParamStr != null) {
+            relativeUrl = relativeUrl + "?" + queryParamStr;
+        }
+
+        br.setRequestId(Long.valueOf(RandomStringUtils.randomNumeric(5)));
+        br.setRelativeUrl(relativeUrl);
+        br.setMethod(HttpMethod.GET);
+        br.setReference(Long.valueOf(RandomStringUtils.randomNumeric(5)));
+        br.setBody("{}");
+
+        return br;
+    }
+
+    /**
+     * Private test context class used since testng runs in parallel to avoid state between tests
+     */
+    private static class TestContext {
+
+        @Mock
+        private UriInfo uriInfo;
+
+        @Mock
+        private LoansApiResource loansApiResource;
+
+        @Captor
+        private ArgumentCaptor<MutableUriInfo> uriInfoCaptor;
+
+        private final GetLoanByIdCommandStrategy underTest;
+
+        TestContext() {
+            MockitoAnnotations.openMocks(this);
+            underTest = new GetLoanByIdCommandStrategy(loansApiResource);
+        }
+    }
+}

fineract-provider/src/test/java/org/apache/fineract/batch/command/internal/GetTransactionByIdCommandStrategyTest.java

@@ -0,0 +1,205 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.batch.command.internal;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.when;
+
+import javax.ws.rs.HttpMethod;
+import javax.ws.rs.core.UriInfo;
+import org.apache.commons.lang3.RandomStringUtils;
+import org.apache.fineract.batch.domain.BatchRequest;
+import org.apache.fineract.batch.domain.BatchResponse;
+import org.apache.fineract.portfolio.loanaccount.api.LoanTransactionsApiResource;
+import org.apache.fineract.portfolio.loanaccount.exception.LoanNotFoundException;
+import org.apache.fineract.portfolio.loanaccount.exception.LoanTransactionNotFoundException;
+import org.apache.http.HttpStatus;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+public class GetTransactionByIdCommandStrategyTest {
+
+    /**
+     * Test {@link GetTransactionByIdCommandStrategy#execute} happy path scenario.
+     */
+    @Test
+    public void testExecuteSuccessScenario() {
+        // given
+        final TestContext testContext = new TestContext();
+
+        final Long loanId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final Long transactionId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final BatchRequest request = getBatchRequest(loanId, transactionId);
+        final String responseBody = "{\"id\":12,\"officeId\":1,\"officeName\":\"Head Office\",\"type\":{\"id\":10,\"code\":"
+                + "\"loanTransactionType.accrual\",\"value\":\"Accrual\",\"disbursement\":false,\"repaymentAtDisbursement\":false,"
+                + "\"repayment\":false,\"contra\":false,\"waiveInterest\":false,\"waiveCharges\":false,\"accrual\":true,\"writeOff\":false,"
+                + "\"recoveryRepayment\":false,\"initiateTransfer\":false,\"approveTransfer\":false,\"withdrawTransfer\":false,"
+                + "\"rejectTransfer\":false,\"chargePayment\":false,\"refund\":false,\"refundForActiveLoans\":false},\"date\":[2022,3,29],"
+                + "\"currency\":{\"code\":\"EUR\",\"name\":\"Euro\",\"decimalPlaces\":2,\"inMultiplesOf\":0,\"displaySymbol\":\"€\","
+                + "\"nameCode\":\"currency.EUR\",\"displayLabel\":\"Euro (€)\"},\"amount\":0.000000,\"netDisbursalAmount\":200.000000,"
+                + "\"principalPortion\":0,\"interestPortion\":0.000000,\"feeChargesPortion\":0,\"penaltyChargesPortion\":0,\"overpaymentPortion\":0,"
+                + "\"unrecognizedIncomePortion\":0,\"outstandingLoanBalance\":0,\"submittedOnDate\":[2022,3,29],\"manuallyReversed\":false,"
+                + "\"loanChargePaidByList\":[],\"numberOfRepayments\":0}";
+
+        given(testContext.loanTransactionsApiResource.retrieveTransaction(loanId, transactionId, testContext.uriInfo))
+                .willReturn(responseBody);
+
+        // when
+        final BatchResponse response = testContext.subjectToTest.execute(request, testContext.uriInfo);
+
+        // then
+        assertThat(response.getStatusCode()).isEqualTo(HttpStatus.SC_OK);
+        assertThat(response.getRequestId()).isEqualTo(request.getRequestId());
+        assertThat(response.getHeaders()).isEqualTo(request.getHeaders());
+        assertThat(response.getBody()).isEqualTo(responseBody);
+    }
+
+    /**
+     * Test {@link GetTransactionByIdCommandStrategy#execute} for internal server error.
+     */
+    @Test
+    public void testExecuteForInternalServerError() {
+        // given
+        final TestContext testContext = new TestContext();
+        final Long loanId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final Long transactionId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final BatchRequest request = getBatchRequest(loanId, transactionId);
+
+        given(testContext.loanTransactionsApiResource.retrieveTransaction(loanId, transactionId, testContext.uriInfo))
+                .willThrow(new RuntimeException("Some error"));
+
+        // when
+        final BatchResponse response = testContext.subjectToTest.execute(request, testContext.uriInfo);
+
+        // then
+        assertThat(response.getStatusCode()).isEqualTo(HttpStatus.SC_INTERNAL_SERVER_ERROR);
+        assertThat(response.getRequestId()).isEqualTo(request.getRequestId());
+        assertThat(response.getHeaders()).isEqualTo(request.getHeaders());
+        assertThat(response.getBody()).isEqualTo("{\"Exception\": java.lang.RuntimeException: Some error}");
+    }
+
+    /**
+     * Test {@link GetTransactionByIdCommandStrategy#execute} for loan not found exception.
+     */
+    @Test
+    public void testExecuteForLoanNotFoundException() {
+        // given
+        final TestContext testContext = new TestContext();
+        final Long loanId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final Long transactionId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final BatchRequest request = getBatchRequest(loanId, transactionId);
+
+        given(testContext.loanTransactionsApiResource.retrieveTransaction(loanId, transactionId, testContext.uriInfo))
+                .willThrow(new LoanNotFoundException(loanId));
+
+        // when
+        final BatchResponse response = testContext.subjectToTest.execute(request, testContext.uriInfo);
+
+        // then
+        assertThat(response.getStatusCode()).isEqualTo(HttpStatus.SC_NOT_FOUND);
+        assertThat(response.getRequestId()).isEqualTo(request.getRequestId());
+        assertThat(response.getHeaders()).isEqualTo(request.getHeaders());
+        assertThat(response.getBody()).isEqualTo(build404NotFoundError("Loan", loanId));
+    }
+
+    /**
+     * Test {@link GetTransactionByIdCommandStrategy#execute} for transaction not found exception.
+     */
+    @Test
+    public void testExecuteForTransactionNotFoundException() {
+        final TestContext testContext = new TestContext();
+        final Long loanId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final Long transactionId = Long.valueOf(RandomStringUtils.randomNumeric(4));
+        final BatchRequest request = getBatchRequest(loanId, transactionId);
+
+        when(testContext.loanTransactionsApiResource.retrieveTransaction(loanId, transactionId, testContext.uriInfo))
+                .thenThrow(new LoanTransactionNotFoundException(transactionId));
+
+        final BatchResponse response = testContext.subjectToTest.execute(request, testContext.uriInfo);
+
+        assertEquals(HttpStatus.SC_NOT_FOUND, response.getStatusCode());
+        assertEquals(build404NotFoundError("Transaction", transactionId), response.getBody());
+        assertEquals(request.getRequestId(), response.getRequestId());
+        assertEquals(request.getHeaders(), response.getHeaders());
+    }
+
+    /**
+     * Creates and returns a request with the given loan id and transaction id.
+     *
+     * @param loanId
+     *            the loan id
+     * @param transactionId
+     *            the transaction id
+     * @return BatchRequest
+     */
+    private BatchRequest getBatchRequest(final Long loanId, final Long transactionId) {
+
+        final BatchRequest br = new BatchRequest();
+        String relativeUrl = "loans/" + loanId + "/transactions/" + transactionId;
+
+        br.setRequestId(Long.valueOf(RandomStringUtils.randomNumeric(5)));
+        br.setRelativeUrl(relativeUrl);
+        br.setMethod(HttpMethod.GET);
+        br.setReference(Long.valueOf(RandomStringUtils.randomNumeric(5)));
+        br.setBody("{}");
+
+        return br;
+    }
+
+    /**
+     * Builds the 404 not found error.
+     *
+     * @param field
+     *            the field name
+     * @param id
+     *            the id
+     */
+    private String build404NotFoundError(final String field, final Long id) {
+        return String.format("{\n" + "  \"developerMessage\": \"The requested resource is not available.\",\n"
+                + "  \"httpStatusCode\": \"404\",\n" + "  \"defaultUserMessage\": \"The requested resource is not available.\",\n"
+                + "  \"userMessageGlobalisationCode\": \"error.msg.resource.not.found\",\n" + "  \"errors\": [\n" + "    {\n"
+                + "      \"developerMessage\": \"%s with identifier %s does not exist\",\n"
+                + "      \"defaultUserMessage\": \"%s with identifier %s does not exist\",\n"
+                + "      \"userMessageGlobalisationCode\": \"error.msg.loan.id.invalid\",\n" + "      \"parameterName\": \"id\",\n"
+                + "      \"args\": [\n" + "        {\n" + "          \"value\": %s\n" + "        }\n" + "      ]\n" + "    }\n" + "  ]\n"
+                + "}", field, id, field, id, id);
+    }
+
+    /**
+     * Private test context class used since testng runs in parallel to avoid state between tests
+     */
+    private static class TestContext {
+
+        @Mock
+        private UriInfo uriInfo;
+
+        @Mock
+        private LoanTransactionsApiResource loanTransactionsApiResource;
+
+        private final GetTransactionByIdCommandStrategy subjectToTest;
+
+        TestContext() {
+            MockitoAnnotations.openMocks(this);
+            subjectToTest = new GetTransactionByIdCommandStrategy(loanTransactionsApiResource);
+        }
+    }
+}

fineract-provider/src/test/java/org/apache/fineract/portfolio/loanaccount/domain/LoanTest.java

@@ -0,0 +1,88 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.portfolio.loanaccount.domain;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+
+import java.math.BigDecimal;
+import java.util.Collection;
+import java.util.Collections;
+import org.apache.fineract.infrastructure.core.service.DateUtils;
+import org.apache.fineract.portfolio.charge.domain.Charge;
+import org.apache.fineract.portfolio.charge.domain.ChargeCalculationType;
+import org.apache.fineract.portfolio.charge.domain.ChargePaymentMode;
+import org.apache.fineract.portfolio.charge.domain.ChargeTimeType;
+import org.junit.jupiter.api.Test;
+import org.springframework.test.util.ReflectionTestUtils;
+
+/**
+ * Tests {@link Loan}.
+ */
+public class LoanTest {
+
+    /**
+     * Tests {@link Loan#getCharges()} with charges.
+     */
+    @Test
+    public void testGetChargesWithCharges() {
+        Loan loan = new Loan();
+        ReflectionTestUtils.setField(loan, "charges", Collections.singleton(buildLoanCharge()));
+
+        final Collection<LoanCharge> chargeIds = loan.getCharges();
+
+        assertEquals(1, chargeIds.size());
+    }
+
+    /**
+     * Tests {@link Loan#getCharges()} with no charges.
+     */
+    @Test
+    public void testGetChargesWithNoCharges() {
+        final Loan loan = new Loan();
+
+        final Collection<LoanCharge> chargeIds = loan.getCharges();
+
+        assertEquals(0, chargeIds.size());
+    }
+
+    /**
+     * Tests {@link Loan#getCharges()} with null to make sure NPE is not thrown.
+     */
+    @Test
+    public void testGetChargesWithNull() {
+        final Loan loan = new Loan();
+        ReflectionTestUtils.setField(loan, "charges", null);
+
+        final Collection<LoanCharge> chargeIds = loan.getCharges();
+
+        assertEquals(0, chargeIds.size());
+    }
+
+    /**
+     * Builds a new loan charge.
+     *
+     * @return the {@link LoanCharge}
+     */
+    private LoanCharge buildLoanCharge() {
+        return new LoanCharge(mock(Loan.class), mock(Charge.class), new BigDecimal(100), new BigDecimal(100),
+                ChargeTimeType.TRANCHE_DISBURSEMENT, ChargeCalculationType.FLAT, DateUtils.getLocalDateOfTenant(),
+                ChargePaymentMode.REGULAR, 1, new BigDecimal(100));
+    }
+}