FINERACT-2389: EMI rounding handling

Author: adamsaghy

fineract-e2e-tests-core/src/test/java/org/apache/fineract/test/factory/LoanProductsRequestFactory.java

@@ -823,7 +823,7 @@ public PostLoanProductsRequest defaultLoanProductsRequestLP2() {
                 .inMultiplesOf(0)//
                 .installmentAmountInMultiplesOf(1)//
                 .useBorrowerCycle(false)//
-                .minPrincipal(100.0)//
+                .minPrincipal(1.0)//
                 .principal(1000.0)//
                 .maxPrincipal(10000.0)//
                 .minNumberOfRepayments(1)//
@@ -1046,7 +1046,7 @@ public PostLoanProductsRequest defaultLoanProductsRequestLP2Emi() {
                 .digitsAfterDecimal(2)//
                 .inMultiplesOf(0)//
                 .useBorrowerCycle(false)//
-                .minPrincipal(10.0)//
+                .minPrincipal(1.0)//
                 .principal(1000.0)//
                 .maxPrincipal(10000.0)//
                 .minNumberOfRepayments(1)//
@@ -1295,7 +1295,7 @@ public PostLoanProductsRequest defaultLoanProductsRequestLP2ChargeOffReasonToExp
                 .inMultiplesOf(0)//
                 .installmentAmountInMultiplesOf(1)//
                 .useBorrowerCycle(false)//
-                .minPrincipal(100.0)//
+                .minPrincipal(1.0)//
                 .principal(1000.0)//
                 .maxPrincipal(10000.0)//
                 .minNumberOfRepayments(1)//
@@ -1534,7 +1534,7 @@ public PostLoanProductsRequest defaultLoanProductsRequestLP2CapitalizedIncome()
                 .inMultiplesOf(0)//
                 .installmentAmountInMultiplesOf(1)//
                 .useBorrowerCycle(false)//
-                .minPrincipal(100.0)//
+                .minPrincipal(1.0)//
                 .principal(1000.0)//
                 .maxPrincipal(10000.0)//
                 .minNumberOfRepayments(1)//

fineract-progressive-loan/src/main/java/org/apache/fineract/portfolio/loanproduct/calc/ProgressiveEMICalculator.java

@@ -1398,11 +1398,23 @@ private void calculateEMIOnNewModelAndMerge(List<RepaymentPeriod> repaymentPerio
 
     private Money applyInstallmentAmountInMultiplesOf(final ProgressiveLoanInterestScheduleModel scheduleModel,
             final Money equalMonthlyInstallment) {
-        return scheduleModel.installmentAmountInMultiplesOf() != null
-                ? Money.roundToMultiplesOf(equalMonthlyInstallment, scheduleModel.installmentAmountInMultiplesOf())
+        return scheduleModel.installmentAmountInMultiplesOf() != null && scheduleModel.installmentAmountInMultiplesOf() > 0
+                ? safeRoundingForEMI(equalMonthlyInstallment, scheduleModel.installmentAmountInMultiplesOf())
                 : equalMonthlyInstallment;
     }
 
+    /**
+     * Rounds the EMI to the nearest multiple of the given number. If the rounded EMI is zero, it adds one multiple of
+     * the given number to it.
+     */
+    private Money safeRoundingForEMI(Money unRoundedEMI, Integer multiplesOf) {
+        Money roundedEMI = Money.roundToMultiplesOf(unRoundedEMI, multiplesOf);
+        if (roundedEMI.isZero()) {
+            roundedEMI = roundedEMI.add(BigDecimal.ONE.multiply(BigDecimal.valueOf(multiplesOf)));
+        }
+        return roundedEMI;
+    }
+
     public EmiAdjustment getEmiAdjustment(final List<RepaymentPeriod> repaymentPeriods) {
         for (int idx = repaymentPeriods.size() - 1; idx > 0; --idx) {
             RepaymentPeriod lastPeriod = repaymentPeriods.get(idx);