Merge branch 'develop'

6 files changed, 875 insertions, 0 deletions

diff --git a/src/test/java/sevenUnits/unit/MultiUnitTest.java b/src/test/java/sevenUnits/unit/MultiUnitTest.java
new file mode 100644
index 0000000..d632118
--- /dev/null
+++ b/src/test/java/sevenUnits/unit/MultiUnitTest.java
@@ -0,0 +1,110 @@
+/**
+ * Copyright (C) 2020 Adrien Hopkins
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package sevenUnits.unit;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+
+import org.junit.jupiter.api.Test;
+
+import sevenUnits.unit.BritishImperial;
+import sevenUnits.unit.MultiUnit;
+import sevenUnits.unit.Metric;
+
+/**
+ * Tests related to the {@code MultiUnit}.
+ *
+ * @since 2020-10-03
+ */
+class MultiUnitTest {
+	
+	@Test
+	final void testConvert() {
+		final Random rng = ThreadLocalRandom.current();
+		final MultiUnit footInch = MultiUnit.of(BritishImperial.Length.FOOT,
+				BritishImperial.Length.INCH);
+		
+		assertEquals(1702.0, footInch.convertTo(Metric.METRE.withPrefix(Metric.MILLI),
+				Arrays.asList(5.0, 7.0)), 1.0);
+		
+		for (int i = 0; i < 1000; i++) {
+			final double feet = rng.nextInt(1000);
+			final double inches = rng.nextDouble() * 12;
+			final double millimetres = feet * 304.8 + inches * 25.4;
+			
+			final List<Double> feetAndInches = Metric.METRE.withPrefix(Metric.MILLI)
+					.convertTo(footInch, millimetres);
+			assertEquals(feet, feetAndInches.get(0), 1e-10);
+			assertEquals(inches, feetAndInches.get(1), 1e-10);
+		}
+	}
+	
+	/**
+	 * Test method for
+	 * {@link sevenUnits.unit.MultiUnit#convertFromBase(double)}.
+	 */
+	@Test
+	final void testConvertFromBase() {
+		final Random rng = ThreadLocalRandom.current();
+		final MultiUnit footInch = MultiUnit.of(BritishImperial.Length.FOOT,
+				BritishImperial.Length.INCH);
+		
+		// 1.7 m =~ 5' + 7"
+		final List<Double> values = footInch.convertFromBase(1.7018);
+		
+		assertEquals(5, values.get(0));
+		assertEquals(7, values.get(1), 1e-12);
+		
+		for (int i = 0; i < 1000; i++) {
+			final double feet = rng.nextInt(1000);
+			final double inches = rng.nextDouble() * 12;
+			final double metres = feet * 0.3048 + inches * 0.0254;
+			
+			final List<Double> feetAndInches = footInch.convertFromBase(metres);
+			assertEquals(feet, feetAndInches.get(0), 1e-10);
+			assertEquals(inches, feetAndInches.get(1), 1e-10);
+		}
+	}
+	
+	/**
+	 * Test method for
+	 * {@link sevenUnits.unit.MultiUnit#convertToBase(java.util.List)}.
+	 */
+	@Test
+	final void testConvertToBase() {
+		final Random rng = ThreadLocalRandom.current();
+		final MultiUnit footInch = MultiUnit.of(BritishImperial.Length.FOOT,
+				BritishImperial.Length.INCH);
+		
+		// 1.7 m =~ 5' + 7"
+		assertEquals(1.7018, footInch.convertToBase(Arrays.asList(5.0, 7.0)),
+				1e-12);
+		
+		for (int i = 0; i < 1000; i++) {
+			final double feet = rng.nextInt(1000);
+			final double inches = rng.nextDouble() * 12;
+			final double metres = feet * 0.3048 + inches * 0.0254;
+			
+			assertEquals(metres,
+					footInch.convertToBase(Arrays.asList(feet, inches)), 1e-12);
+		}
+	}
+}
diff --git a/src/test/java/sevenUnits/unit/UnitDatabaseTest.java b/src/test/java/sevenUnits/unit/UnitDatabaseTest.java
new file mode 100644
index 0000000..1d5e503
--- /dev/null
+++ b/src/test/java/sevenUnits/unit/UnitDatabaseTest.java
@@ -0,0 +1,317 @@
+/**
+ * Copyright (C) 2019 Adrien Hopkins
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package sevenUnits.unit;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.NoSuchElementException;
+import java.util.Set;
+
+import org.junit.jupiter.api.Test;
+
+import sevenUnits.unit.LinearUnit;
+import sevenUnits.unit.NameSymbol;
+import sevenUnits.unit.Metric;
+import sevenUnits.unit.Unit;
+import sevenUnits.unit.UnitDatabase;
+import sevenUnits.unit.UnitPrefix;
+
+/**
+ * A test for the {@link UnitDatabase} class. This is NOT part of this program's
+ * public API.
+ * 
+ * @author Adrien Hopkins
+ * @since 2019-04-14
+ * @since v0.2.0
+ */
+class UnitDatabaseTest {
+	// some linear units and one nonlinear
+	private static final Unit U = Metric.METRE;
+	private static final Unit V = Metric.KILOGRAM;
+	private static final Unit W = Metric.SECOND;
+	
+	// used for testing expressions
+	// J = U^2 * V / W^2
+	private static final LinearUnit J = Metric.KILOGRAM.times(Metric.METRE.toExponent(2))
+			.dividedBy(Metric.SECOND.toExponent(2));
+	private static final LinearUnit K = Metric.KELVIN;
+	
+	private static final Unit NONLINEAR = Unit
+			.fromConversionFunctions(Metric.METRE.getBase(), o -> o + 1, o -> o - 1);
+	
+	// make the prefix values prime so I can tell which multiplications were made
+	private static final UnitPrefix A = UnitPrefix.valueOf(2)
+			.withName(NameSymbol.ofName("A"));
+	private static final UnitPrefix B = UnitPrefix.valueOf(3)
+			.withName(NameSymbol.ofName("B"));
+	private static final UnitPrefix C = UnitPrefix.valueOf(5)
+			.withName(NameSymbol.ofName("C"));
+	private static final UnitPrefix AB = UnitPrefix.valueOf(7);
+	private static final UnitPrefix BC = UnitPrefix.valueOf(11);
+	
+	/**
+	 * Confirms that operations that shouldn't function for infinite databases
+	 * throw an {@code IllegalStateException}.
+	 * 
+	 * @since 2019-05-03
+	 */
+//	@Test
+//	@Timeout(value = 1, unit = TimeUnit.SECONDS)
+	public void testInfiniteSetExceptions() {
+		// load units
+		final UnitDatabase infiniteDatabase = new UnitDatabase();
+		
+		infiniteDatabase.addUnit("J", J);
+		infiniteDatabase.addUnit("K", K);
+		
+		infiniteDatabase.addPrefix("A", A);
+		infiniteDatabase.addPrefix("B", B);
+		infiniteDatabase.addPrefix("C", C);
+		
+		final Set<Entry<String, Unit>> entrySet = infiniteDatabase.unitMap()
+				.entrySet();
+		final Set<String> keySet = infiniteDatabase.unitMap().keySet();
+		assertThrows(IllegalStateException.class, () -> entrySet.toArray());
+		assertThrows(IllegalStateException.class, () -> keySet.toArray());
+	}
+	
+	/**
+	 * Test that prefixes correctly apply to units.
+	 * 
+	 * @since 2019-04-14
+	 * @since v0.2.0
+	 */
+	@Test
+	public void testPrefixes() {
+		final UnitDatabase database = new UnitDatabase();
+		
+		database.addUnit("U", U);
+		database.addUnit("V", V);
+		database.addUnit("W", W);
+		
+		database.addPrefix("A", A);
+		database.addPrefix("B", B);
+		database.addPrefix("C", C);
+		
+		// test the getPrefixesFromName method
+		final List<UnitPrefix> expected = Arrays.asList(C, B, A);
+		assertEquals(expected, database.getPrefixesFromName("ABCU"));
+		
+		// get the product
+		final Unit abcuNonlinear = database.getUnit("ABCU");
+		assert abcuNonlinear instanceof LinearUnit;
+		
+		final LinearUnit abcu = (LinearUnit) abcuNonlinear;
+		assertEquals(A.getMultiplier() * B.getMultiplier() * C.getMultiplier(),
+				abcu.getConversionFactor(), 1e-15);
+	}
+	
+	/**
+	 * Tests the functionnalites of the prefixless unit map.
+	 * 
+	 * <p>
+	 * The map should be an auto-updating view of the units in the database.
+	 * </p>
+	 * 
+	 * @since 2019-04-14
+	 * @since v0.2.0
+	 */
+	@Test
+	public void testPrefixlessUnitMap() {
+		final UnitDatabase database = new UnitDatabase();
+		final Map<String, Unit> prefixlessUnits = database
+				.unitMapPrefixless(true);
+		
+		database.addUnit("U", U);
+		database.addUnit("V", V);
+		database.addUnit("W", W);
+		
+		// this should work because the map should be an auto-updating view
+		assertTrue(prefixlessUnits.containsKey("U"));
+		assertFalse(prefixlessUnits.containsKey("Z"));
+		
+		assertTrue(prefixlessUnits.containsValue(U));
+		assertFalse(prefixlessUnits.containsValue(NONLINEAR));
+	}
+	
+	/**
+	 * Tests that the database correctly stores and retrieves units, ignoring
+	 * prefixes.
+	 * 
+	 * @since 2019-04-14
+	 * @since v0.2.0
+	 */
+	@Test
+	public void testPrefixlessUnits() {
+		final UnitDatabase database = new UnitDatabase();
+		
+		database.addUnit("U", U);
+		database.addUnit("V", V);
+		database.addUnit("W", W);
+		
+		assertTrue(database.containsUnitName("U"));
+		assertFalse(database.containsUnitName("Z"));
+		
+		assertEquals(U, database.getUnit("U"));
+		assertThrows(NoSuchElementException.class, () -> database.getUnit("Z"));
+	}
+	
+	/**
+	 * Test that unit expressions return the correct value.
+	 * 
+	 * @since 2019-04-14
+	 * @since v0.2.0
+	 */
+	@Test
+	public void testUnitExpressions() {
+		// load units
+		final UnitDatabase database = new UnitDatabase();
+		
+		database.addUnit("U", U);
+		database.addUnit("V", V);
+		database.addUnit("W", W);
+		database.addUnit("fj", J.times(5));
+		database.addUnit("ej", J.times(8));
+		
+		database.addPrefix("A", A);
+		database.addPrefix("B", B);
+		database.addPrefix("C", C);
+		
+		// first test - test prefixes and operations
+		final Unit expected1 = J.withPrefix(A).withPrefix(B).withPrefix(C)
+				.withPrefix(C);
+		final Unit actual1 = database.getUnitFromExpression("ABV * CU^2 / W / W");
+		
+		assertEquals(expected1, actual1);
+		
+		// second test - test addition and subtraction
+		final Unit expected2 = J.times(58);
+		final Unit actual2 = database.getUnitFromExpression("2 fj + 6 ej");
+		
+		assertEquals(expected2, actual2);
+	}
+	
+	/**
+	 * Tests both the unit name iterator and the name-unit entry iterator
+	 * 
+	 * @since 2019-04-14
+	 * @since v0.2.0
+	 */
+	@Test
+	public void testUnitIterator() {
+		// load units
+		final UnitDatabase database = new UnitDatabase();
+		
+		database.addUnit("J", J);
+		database.addUnit("K", K);
+		
+		database.addPrefix("A", A);
+		database.addPrefix("B", B);
+		database.addPrefix("C", C);
+		
+		final int NUM_UNITS = database.unitMapPrefixless(true).size();
+		final int NUM_PREFIXES = database.prefixMap().size();
+		
+		final Iterator<String> nameIterator = database.unitMap().keySet()
+				.iterator();
+		final Iterator<Entry<String, Unit>> entryIterator = database.unitMap()
+				.entrySet().iterator();
+		
+		int expectedLength = 1;
+		int unitsWithThisLengthSoFar = 0;
+		
+		// loop 1000 times
+		for (int i = 0; i < 1000; i++) {
+			// expected length of next
+			if (unitsWithThisLengthSoFar >= NUM_UNITS
+					* (int) Math.pow(NUM_PREFIXES, expectedLength - 1)) {
+				expectedLength++;
+				unitsWithThisLengthSoFar = 0;
+			}
+			
+			// test that stuff is valid
+			final String nextName = nameIterator.next();
+			final Unit nextUnit = database.getUnit(nextName);
+			final Entry<String, Unit> nextEntry = entryIterator.next();
+			
+			assertEquals(expectedLength, nextName.length());
+			assertEquals(nextName, nextEntry.getKey());
+			assertEquals(nextUnit, nextEntry.getValue());
+			
+			unitsWithThisLengthSoFar++;
+		}
+		
+		// test toString for consistency
+		final String entryIteratorString = entryIterator.toString();
+		for (int i = 0; i < 3; i++) {
+			assertEquals(entryIteratorString, entryIterator.toString());
+		}
+		
+		final String nameIteratorString = nameIterator.toString();
+		for (int i = 0; i < 3; i++) {
+			assertEquals(nameIteratorString, nameIterator.toString());
+		}
+	}
+	
+	/**
+	 * Determine, given a unit name that could mean multiple things, which
+	 * meaning is chosen.
+	 * <p>
+	 * For example, "ABCU" could mean "A-B-C-U", "AB-C-U", or "A-BC-U". In this
+	 * case, "AB-C-U" is the correct choice.
+	 * </p>
+	 * 
+	 * @since 2019-04-14
+	 * @since v0.2.0
+	 */
+	@Test
+	public void testUnitPrefixCombinations() {
+		// load units
+		final UnitDatabase database = new UnitDatabase();
+		
+		database.addUnit("J", J);
+		
+		database.addPrefix("A", A);
+		database.addPrefix("B", B);
+		database.addPrefix("C", C);
+		database.addPrefix("AB", AB);
+		database.addPrefix("BC", BC);
+		
+		// test 1 - AB-C-J vs A-BC-J vs A-B-C-J
+		final Unit expected1 = J.withPrefix(AB).withPrefix(C);
+		final Unit actual1 = database.getUnit("ABCJ");
+		
+		assertEquals(expected1, actual1);
+		
+		// test 2 - ABC-J vs AB-CJ vs AB-C-J
+		database.addUnit("CJ", J.times(13));
+		database.addPrefix("ABC", UnitPrefix.valueOf(17));
+		
+		final Unit expected2 = J.times(17);
+		final Unit actual2 = database.getUnit("ABCJ");
+		
+		assertEquals(expected2, actual2);
+	}
+}
diff --git a/src/test/java/sevenUnits/unit/UnitTest.java b/src/test/java/sevenUnits/unit/UnitTest.java
new file mode 100644
index 0000000..a980054
--- /dev/null
+++ b/src/test/java/sevenUnits/unit/UnitTest.java
@@ -0,0 +1,153 @@
+/**
+ * Copyright (C) 2018 Adrien Hopkins
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package sevenUnits.unit;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+
+import org.junit.jupiter.api.Test;
+
+import sevenUnits.unit.LinearUnit;
+import sevenUnits.unit.LinearUnitValue;
+import sevenUnits.unit.NameSymbol;
+import sevenUnits.unit.Metric;
+import sevenUnits.unit.Unit;
+import sevenUnits.unit.UnitValue;
+import sevenUnits.utils.DecimalComparison;
+
+/**
+ * Testing the various Unit classes. This is NOT part of this program's public
+ * API.
+ * 
+ * @author Adrien Hopkins
+ * @since 2018-12-22
+ * @since v0.1.0
+ */
+class UnitTest {
+	/** A random number generator */
+	private static final Random rng = ThreadLocalRandom.current();
+	
+	@Test
+	public void testAdditionAndSubtraction() {
+		final LinearUnit inch = Metric.METRE.times(0.0254)
+				.withName(NameSymbol.of("inch", "in"));
+		final LinearUnit foot = Metric.METRE.times(0.3048)
+				.withName(NameSymbol.of("foot", "ft"));
+		
+		assertEquals(inch.plus(foot), Metric.METRE.times(0.3302));
+		assertEquals(foot.minus(inch), Metric.METRE.times(0.2794));
+		
+		// test with LinearUnitValue
+		final LinearUnitValue value1 = LinearUnitValue.getExact(Metric.METRE, 15);
+		final LinearUnitValue value2 = LinearUnitValue.getExact(foot, 120);
+		final LinearUnitValue value3 = LinearUnitValue.getExact(Metric.METRE, 0.5);
+		final LinearUnitValue value4 = LinearUnitValue.getExact(Metric.KILOGRAM, 60);
+		
+		// make sure addition is done correctly
+		assertEquals(51.576, value1.plus(value2).getValueExact(), 0.001);
+		assertEquals(15.5, value1.plus(value3).getValueExact());
+		assertEquals(52.076, value1.plus(value2).plus(value3).getValueExact(),
+				0.001);
+		
+		// make sure addition uses the correct unit, and is still associative
+		// (ignoring floating-point rounding errors)
+		assertEquals(Metric.METRE, value1.plus(value2).getUnit());
+		assertEquals(Metric.METRE, value1.plus(value2).plus(value3).getUnit());
+		assertEquals(foot, value2.plus(value1).getUnit());
+		assertTrue(value1.plus(value2).equals(value2.plus(value1), true));
+		
+		// make sure errors happen when they should
+		assertThrows(IllegalArgumentException.class, () -> value1.plus(value4));
+	}
+	
+	@Test
+	public void testConversion() {
+		final LinearUnit metre = Metric.METRE;
+		final Unit inch = metre.times(0.0254);
+		
+		final UnitValue value = UnitValue.of(inch, 75);
+		
+		assertEquals(1.9, inch.convertTo(metre, 75), 0.01);
+		assertEquals(1.9, value.convertTo(metre).getValue(), 0.01);
+		
+		// try random stuff
+		for (int i = 0; i < 1000; i++) {
+			// initiate random values
+			final double conversionFactor = UnitTest.rng.nextDouble() * 1000000;
+			final double testValue = UnitTest.rng.nextDouble() * 1000000;
+			final double expected = testValue * conversionFactor;
+			
+			// test
+			final Unit unit = Metric.METRE.times(conversionFactor);
+			final double actual = unit.convertToBase(testValue);
+			
+			assertEquals(actual, expected,
+					expected * DecimalComparison.DOUBLE_EPSILON);
+		}
+	}
+	
+	@Test
+	public void testEquals() {
+		final LinearUnit metre = Metric.METRE;
+		final Unit meter = Metric.BaseUnits.METRE.asLinearUnit();
+		
+		assertEquals(metre, meter);
+	}
+	
+	@Test
+	public void testIsMetric() {
+		final Unit metre = Metric.METRE;
+		final Unit megasecond = Metric.SECOND.withPrefix(Metric.MEGA);
+		final Unit hour = Metric.HOUR;
+		
+		assertTrue(metre.isMetric());
+		assertTrue(megasecond.isMetric());
+		assertFalse(hour.isMetric());
+	}
+	
+	@Test
+	public void testMultiplicationAndDivision() {
+		// test unit-times-unit multiplication
+		final LinearUnit generatedJoule = Metric.KILOGRAM
+				.times(Metric.METRE.toExponent(2)).dividedBy(Metric.SECOND.toExponent(2));
+		final LinearUnit actualJoule = Metric.JOULE;
+		
+		assertEquals(generatedJoule, actualJoule);
+		
+		// test multiplication by conversion factors
+		final LinearUnit kilometre = Metric.METRE.times(1000);
+		final LinearUnit hour = Metric.SECOND.times(3600);
+		final LinearUnit generatedKPH = kilometre.dividedBy(hour);
+		
+		final LinearUnit actualKPH = Metric.METRE.dividedBy(Metric.SECOND).dividedBy(3.6);
+		
+		assertEquals(generatedKPH, actualKPH);
+	}
+	
+	@Test
+	public void testPrefixes() {
+		final LinearUnit generatedKilometre = Metric.METRE.withPrefix(Metric.KILO);
+		final LinearUnit actualKilometre = Metric.METRE.times(1000);
+		
+		assertEquals(generatedKilometre, actualKilometre);
+	}
+}
diff --git a/src/test/java/sevenUnits/utils/ConditionalExistenceCollectionsTest.java b/src/test/java/sevenUnits/utils/ConditionalExistenceCollectionsTest.java
new file mode 100644
index 0000000..46afe77
--- /dev/null
+++ b/src/test/java/sevenUnits/utils/ConditionalExistenceCollectionsTest.java
@@ -0,0 +1,161 @@
+/**
+ * Copyright (C) 2019 Adrien Hopkins
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package sevenUnits.utils;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.NoSuchElementException;
+
+import org.junit.jupiter.api.Test;
+
+import sevenUnits.utils.ConditionalExistenceCollections;
+import sevenUnits.utils.ConditionalExistenceCollections.ConditionalExistenceIterator;
+
+/**
+ * Tests the {@link #ConditionalExistenceCollections}.
+ * 
+ * @author Adrien Hopkins
+ * @since 2019-10-16
+ */
+class ConditionalExistenceCollectionsTest {
+
+	/**
+	 * The returned iterator ignores elements that don't start with "a".
+	 * 
+	 * @return test iterator
+	 * @since 2019-10-17
+	 */
+	ConditionalExistenceIterator<String> getTestIterator() {
+		final List<String> items = Arrays.asList("aa", "ab", "ba");
+		final Iterator<String> it = items.iterator();
+		final ConditionalExistenceIterator<String> cit = (ConditionalExistenceIterator<String>) ConditionalExistenceCollections
+				.conditionalExistenceIterator(it, s -> s.startsWith("a"));
+		return cit;
+	}
+
+	/**
+	 * The returned map ignores mappings where the value is zero.
+	 * 
+	 * @return map to be used for test data
+	 * @since 2019-10-16
+	 */
+	Map<String, Integer> getTestMap() {
+		final Map<String, Integer> map = new HashMap<>();
+		map.put("one", 1);
+		map.put("two", 2);
+		map.put("zero", 0);
+		map.put("ten", 10);
+		final Map<String, Integer> conditionalMap = ConditionalExistenceCollections.conditionalExistenceMap(map,
+				e -> !Integer.valueOf(0).equals(e.getValue()));
+		return conditionalMap;
+	}
+
+	/**
+	 * Test method for {@link org.unitConverter.math.ZeroIsNullMap#containsKey(java.lang.Object)}.
+	 */
+	@Test
+	void testContainsKeyObject() {
+		final Map<String, Integer> map = this.getTestMap();
+		assertTrue(map.containsKey("one"));
+		assertTrue(map.containsKey("ten"));
+		assertFalse(map.containsKey("five"));
+		assertFalse(map.containsKey("zero"));
+	}
+
+	/**
+	 * Test method for {@link org.unitConverter.math.ZeroIsNullMap#containsValue(java.lang.Object)}.
+	 */
+	@Test
+	void testContainsValueObject() {
+		final Map<String, Integer> map = this.getTestMap();
+		assertTrue(map.containsValue(1));
+		assertTrue(map.containsValue(10));
+		assertFalse(map.containsValue(5));
+		assertFalse(map.containsValue(0));
+	}
+
+	/**
+	 * Test method for {@link org.unitConverter.math.ZeroIsNullMap#entrySet()}.
+	 */
+	@Test
+	void testEntrySet() {
+		final Map<String, Integer> map = this.getTestMap();
+		for (final Entry<String, Integer> e : map.entrySet()) {
+			assertTrue(e.getValue() != 0);
+		}
+	}
+
+	/**
+	 * Test method for {@link org.unitConverter.math.ZeroIsNullMap#get(java.lang.Object)}.
+	 */
+	@Test
+	void testGetObject() {
+		final Map<String, Integer> map = this.getTestMap();
+		assertEquals(1, map.get("one"));
+		assertEquals(10, map.get("ten"));
+		assertEquals(null, map.get("five"));
+		assertEquals(null, map.get("zero"));
+	}
+
+	@Test
+	void testIterator() {
+		final ConditionalExistenceIterator<String> testIterator = this.getTestIterator();
+
+		assertTrue(testIterator.hasNext);
+		assertTrue(testIterator.hasNext());
+		assertEquals("aa", testIterator.nextElement);
+		assertEquals("aa", testIterator.next());
+
+		assertTrue(testIterator.hasNext);
+		assertTrue(testIterator.hasNext());
+		assertEquals("ab", testIterator.nextElement);
+		assertEquals("ab", testIterator.next());
+
+		assertFalse(testIterator.hasNext);
+		assertFalse(testIterator.hasNext());
+		assertEquals(null, testIterator.nextElement);
+		assertThrows(NoSuchElementException.class, testIterator::next);
+	}
+
+	/**
+	 * Test method for {@link org.unitConverter.math.ZeroIsNullMap#keySet()}.
+	 */
+	@Test
+	void testKeySet() {
+		final Map<String, Integer> map = this.getTestMap();
+		assertFalse(map.keySet().contains("zero"));
+	}
+
+	/**
+	 * Test method for {@link org.unitConverter.math.ZeroIsNullMap#values()}.
+	 */
+	@Test
+	void testValues() {
+		final Map<String, Integer> map = this.getTestMap();
+		assertFalse(map.values().contains(0));
+	}
+
+}
diff --git a/src/test/java/sevenUnits/utils/ExpressionParserTest.java b/src/test/java/sevenUnits/utils/ExpressionParserTest.java
new file mode 100644
index 0000000..29648ee
--- /dev/null
+++ b/src/test/java/sevenUnits/utils/ExpressionParserTest.java
@@ -0,0 +1,54 @@
+/**
+ * Copyright (C) 2019 Adrien Hopkins
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package sevenUnits.utils;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+import sevenUnits.utils.ExpressionParser;
+
+/**
+ * A test for the {@code ExpressionParser} class. This is NOT part of this program's public API.
+ * 
+ * @author Adrien Hopkins
+ * @since 2019-03-22
+ * @since v0.2.0
+ */
+class ExpressionParserTest {
+	private static final ExpressionParser<Integer> numberParser = new ExpressionParser.Builder<>(Integer::parseInt)
+			.addBinaryOperator("+", (o1, o2) -> o1 + o2, 0).addBinaryOperator("-", (o1, o2) -> o1 - o2, 0)
+			.addBinaryOperator("*", (o1, o2) -> o1 * o2, 1).addBinaryOperator("/", (o1, o2) -> o1 / o2, 1)
+			.addBinaryOperator("^", (o1, o2) -> (int) Math.pow(o1, o2), 2).build();
+
+	/**
+	 * Test method for {@link sevenUnits.utils.ExpressionParser#parseExpression(java.lang.String)}.
+	 */
+	@Test
+	public void testParseExpression() {
+		// test parsing of expressions
+		assertEquals((int) numberParser.parseExpression("1 + 2 ^ 5 * 3"), 97);
+		assertEquals((int) numberParser.parseExpression("(1 + 2) ^ 5 * 3"), 729);
+
+		// ensure it normally goes left to right
+		assertEquals((int) numberParser.parseExpression("1 + 2 + 3 + 4"), 10);
+		assertEquals((int) numberParser.parseExpression("12 - 4 - 3"), 5);
+		assertEquals((int) numberParser.parseExpression("12 - (4 - 3)"), 11);
+		assertEquals((int) numberParser.parseExpression("1 / 2 + 3"), 3);
+	}
+
+}
diff --git a/src/test/java/sevenUnits/utils/ObjectProductTest.java b/src/test/java/sevenUnits/utils/ObjectProductTest.java
new file mode 100644
index 0000000..13fd7ec
--- /dev/null
+++ b/src/test/java/sevenUnits/utils/ObjectProductTest.java
@@ -0,0 +1,80 @@
+/**
+ * Copyright (C) 2018 Adrien Hopkins
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package sevenUnits.utils;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static sevenUnits.unit.Metric.Dimensions.AREA;
+import static sevenUnits.unit.Metric.Dimensions.ENERGY;
+import static sevenUnits.unit.Metric.Dimensions.LENGTH;
+import static sevenUnits.unit.Metric.Dimensions.MASS;
+import static sevenUnits.unit.Metric.Dimensions.MASS_DENSITY;
+import static sevenUnits.unit.Metric.Dimensions.QUANTITY;
+import static sevenUnits.unit.Metric.Dimensions.TIME;
+import static sevenUnits.unit.Metric.Dimensions.VOLUME;
+
+import org.junit.jupiter.api.Test;
+
+import sevenUnits.unit.Metric;
+import sevenUnits.utils.ObjectProduct;
+
+/**
+ * Tests for {@link ObjectProduct} using BaseDimension as a test object. This is NOT part of this program's public API.
+ * 
+ * @author Adrien Hopkins
+ * @since 2018-12-12
+ * @since v0.1.0
+ */
+class ObjectProductTest {
+	/**
+	 * Tests {@link UnitDimension#equals}
+	 * 
+	 * @since 2018-12-12
+	 * @since v0.1.0
+	 */
+	@Test
+	public void testEquals() {
+		assertEquals(LENGTH, LENGTH);
+		assertFalse(LENGTH.equals(QUANTITY));
+	}
+
+	/**
+	 * Tests {@code UnitDimension}'s exponentiation
+	 * 
+	 * @since 2019-01-15
+	 * @since v0.1.0
+	 */
+	@Test
+	public void testExponents() {
+		assertEquals(1, LENGTH.getExponent(Metric.BaseDimensions.LENGTH));
+		assertEquals(3, VOLUME.getExponent(Metric.BaseDimensions.LENGTH));
+	}
+
+	/**
+	 * Tests {@code UnitDimension}'s multiplication and division.
+	 * 
+	 * @since 2018-12-12
+	 * @since v0.1.0
+	 */
+	@Test
+	public void testMultiplicationAndDivision() {
+		assertEquals(AREA, LENGTH.times(LENGTH));
+		assertEquals(MASS_DENSITY, MASS.dividedBy(VOLUME));
+		assertEquals(ENERGY, AREA.times(MASS).dividedBy(TIME).dividedBy(TIME));
+		assertEquals(LENGTH, LENGTH.times(TIME).dividedBy(TIME));
+	}
+}