JUnit Test Overview

The NeqSim project contains an extensive JUnit 5 test suite. The tests are grouped by feature area under src/test/java/neqsim. The main groups are summarised below.

Thermodynamic operations

Directory: src/test/java/neqsim/thermodynamicoperations

Tests for the core thermodynamic calculation utilities. The flashops package verifies different flash calculations (TP, PH, PS etc.) while phaseenvelopeops checks phase envelope algorithms. Utilities and common operations are tested under util.

PVT simulations

Directory: src/test/java/neqsim/pvtsimulation/simulation

Covers simulation models used for PVT studies such as constant volume depletion, differential liberation and slim‑tube simulations. These tests ensure that the simulation workflow and calculated properties are consistent.

Process modelling

Directory: src/test/java/neqsim/process

Tests of the dynamic process models and process equipment. Examples include separator, compressor and process controller behaviour.

Compressor Test Files

Test File	Description
CompressorTest.java	Core compressor calculations, polytropic method, efficiency
CompressorChartTest.java	Performance curve interpolation, surge/stone wall
CompressorChartGeneratorTest.java	Automatic curve generation from templates
CompressorChartMWInterpolationTest.java	Multi-map MW interpolation
CompressorChartKhader2015Test.java	Khader 2015 method with fan law scaling
CompressorMechanicalLossesTest.java	Seal gas consumption (API 692) and bearing losses (API 617)
ASMEPTC10ValidationTest.java	Validation against ASME PTC 10 standard
CompressorDynamicSimulationTest.java	Dynamic simulation, startup/shutdown profiles
SafeSplineSurgeCurveTest.java	Spline-based surge curve with safe extrapolation

Physical properties and fluid mechanics

Directories:

• src/test/java/neqsim/physicalproperties
• src/test/java/neqsim/fluidmechanics

Focus on methods for viscosity, density and other property models together with flow system calculations.

Fluid Mechanics Test Files

Test File	Description
TwoPhasePipeFlowSystemTest.java	System setup, steady-state solving, mass/heat transfer, model comparisons
NonEquilibriumPipeFlowTest.java	Non-equilibrium mass transfer, evaporation, dissolution, bidirectional transfer
FlowPatternDetectorTest.java	Flow pattern detection (Taitel-Dukler, Baker, Barnea, Beggs-Brill)
InterfacialAreaCalculatorTest.java	Interfacial area calculations for all flow patterns
MassTransferCoefficientCalculatorTest.java	Mass transfer coefficient correlations
TwoPhasePipeFlowSystemBuilderTest.java	Builder API tests

Chemical reactions and thermo

Directories:

• src/test/java/neqsim/chemicalreactions
• src/test/java/neqsim/thermo

Verify reaction models and the underlying thermodynamic phase implementations.

Utilities, statistics and standards

Directories:

• src/test/java/neqsim/util
• src/test/java/neqsim/statistics
• src/test/java/neqsim/standards

Contain unit tests for helper utilities (database connectors, units), statistical calculations and implementation of industry standards.

Running the tests

All tests can be executed with Maven:

mvn test

Use the Maven wrapper (./mvnw test) when Maven is not installed. To run a specific test class you can supply the class name:

mvn -Dtest=ClassName test

A code coverage report can be produced using Jacoco:

mvn jacoco:prepare-agent test install jacoco:report

The resulting report is written to target/site/jacoco/index.html.