Added a full suite of frontend tests

(Added tests for the settings and unit/prefix viewer parts of the GUI, which are
not yet implemented)

5 files changed, 482 insertions, 103 deletions

diff --git a/src/main/java/sevenUnits/unit/UnitPrefix.java b/src/main/java/sevenUnits/unit/UnitPrefix.java
index bf9d1fd..e1f7788 100644
--- a/src/main/java/sevenUnits/unit/UnitPrefix.java
+++ b/src/main/java/sevenUnits/unit/UnitPrefix.java
@@ -17,69 +17,59 @@
 package sevenUnits.unit;
 
 import java.util.Objects;
-import java.util.Optional;
-import java.util.Set;
 
 import sevenUnits.utils.DecimalComparison;
 import sevenUnits.utils.NameSymbol;
+import sevenUnits.utils.Nameable;
 
 /**
- * A prefix that can be applied to a {@code LinearUnit} to multiply it by some value
+ * A prefix that can be applied to a {@code LinearUnit} to multiply it by some
+ * value
  * 
  * @author Adrien Hopkins
  * @since 2019-10-16
  */
-public final class UnitPrefix {
+public final class UnitPrefix implements Nameable {
 	/**
 	 * Gets a {@code UnitPrefix} from a multiplier
 	 * 
-	 * @param multiplier
-	 *            multiplier of prefix
+	 * @param multiplier multiplier of prefix
 	 * @return prefix
 	 * @since 2019-10-16
 	 */
 	public static UnitPrefix valueOf(final double multiplier) {
 		return new UnitPrefix(multiplier, NameSymbol.EMPTY);
 	}
-
+	
 	/**
 	 * Gets a {@code UnitPrefix} from a multiplier and a name
 	 * 
-	 * @param multiplier
-	 *            multiplier of prefix
-	 * @param ns
-	 *            name(s) and symbol of prefix
+	 * @param multiplier multiplier of prefix
+	 * @param ns         name(s) and symbol of prefix
 	 * @return prefix
 	 * @since 2019-10-16
-	 * @throws NullPointerException
-	 *             if ns is null
+	 * @throws NullPointerException if ns is null
 	 */
-	public static UnitPrefix valueOf(final double multiplier, final NameSymbol ns) {
-		return new UnitPrefix(multiplier, Objects.requireNonNull(ns, "ns must not be null."));
+	public static UnitPrefix valueOf(final double multiplier,
+			final NameSymbol ns) {
+		return new UnitPrefix(multiplier,
+				Objects.requireNonNull(ns, "ns must not be null."));
 	}
-
-	/**
-	 * This prefix's primary name
-	 */
-	private final Optional<String> primaryName;
-
-	/**
-	 * This prefix's symbol
-	 */
-	private final Optional<String> symbol;
-
+	
 	/**
-	 * Other names and symbols used by this prefix
+	 * This prefix's name(s) and symbol.
+	 * 
+	 * @since 2022-04-16
 	 */
-	private final Set<String> otherNames;
-
+	private final NameSymbol nameSymbol;
+	
 	/**
 	 * The number that this prefix multiplies units by
 	 * 
 	 * @since 2019-10-16
 	 */
 	private final double multiplier;
-
+	
 	/**
 	 * Creates the {@code DefaultUnitPrefix}.
 	 * 
@@ -89,28 +79,24 @@ public final class UnitPrefix {
 	 */
 	private UnitPrefix(final double multiplier, final NameSymbol ns) {
 		this.multiplier = multiplier;
-		this.primaryName = ns.getPrimaryName();
-		this.symbol = ns.getSymbol();
-		this.otherNames = ns.getOtherNames();
+		this.nameSymbol = ns;
 	}
-
+	
 	/**
 	 * Divides this prefix by a scalar
 	 * 
-	 * @param divisor
-	 *            number to divide by
+	 * @param divisor number to divide by
 	 * @return quotient of prefix and scalar
 	 * @since 2019-10-16
 	 */
 	public UnitPrefix dividedBy(final double divisor) {
 		return valueOf(this.getMultiplier() / divisor);
 	}
-
+	
 	/**
 	 * Divides this prefix by {@code other}.
 	 * 
-	 * @param other
-	 *            prefix to divide by
+	 * @param other prefix to divide by
 	 * @return quotient of prefixes
 	 * @since 2019-04-13
 	 * @since v0.2.0
@@ -118,7 +104,7 @@ public final class UnitPrefix {
 	public UnitPrefix dividedBy(final UnitPrefix other) {
 		return valueOf(this.getMultiplier() / other.getMultiplier());
 	}
-
+	
 	/**
 	 * {@inheritDoc}
 	 * 
@@ -133,9 +119,10 @@ public final class UnitPrefix {
 		if (!(obj instanceof UnitPrefix))
 			return false;
 		final UnitPrefix other = (UnitPrefix) obj;
-		return DecimalComparison.equals(this.getMultiplier(), other.getMultiplier());
+		return DecimalComparison.equals(this.getMultiplier(),
+				other.getMultiplier());
 	}
-
+	
 	/**
 	 * @return prefix's multiplier
 	 * @since 2019-11-26
@@ -143,31 +130,12 @@ public final class UnitPrefix {
 	public double getMultiplier() {
 		return this.multiplier;
 	}
-
-	/**
-	 * @return other names
-	 * @since 2019-11-26
-	 */
-	public final Set<String> getOtherNames() {
-		return this.otherNames;
-	}
-
-	/**
-	 * @return primary name
-	 * @since 2019-11-26
-	 */
-	public final Optional<String> getPrimaryName() {
-		return this.primaryName;
-	}
-
-	/**
-	 * @return symbol
-	 * @since 2019-11-26
-	 */
-	public final Optional<String> getSymbol() {
-		return this.symbol;
+	
+	@Override
+	public NameSymbol getNameSymbol() {
+		return this.nameSymbol;
 	}
-
+	
 	/**
 	 * {@inheritDoc}
 	 * 
@@ -177,24 +145,22 @@ public final class UnitPrefix {
 	public int hashCode() {
 		return DecimalComparison.hash(this.getMultiplier());
 	}
-
+	
 	/**
 	 * Multiplies this prefix by a scalar
 	 * 
-	 * @param multiplicand
-	 *            number to multiply by
+	 * @param multiplicand number to multiply by
 	 * @return product of prefix and scalar
 	 * @since 2019-10-16
 	 */
 	public UnitPrefix times(final double multiplicand) {
 		return valueOf(this.getMultiplier() * multiplicand);
 	}
-
+	
 	/**
 	 * Multiplies this prefix by {@code other}.
 	 * 
-	 * @param other
-	 *            prefix to multiply by
+	 * @param other prefix to multiply by
 	 * @return product of prefixes
 	 * @since 2019-04-13
 	 * @since v0.2.0
@@ -202,12 +168,11 @@ public final class UnitPrefix {
 	public UnitPrefix times(final UnitPrefix other) {
 		return valueOf(this.getMultiplier() * other.getMultiplier());
 	}
-
+	
 	/**
 	 * Raises this prefix to an exponent.
 	 * 
-	 * @param exponent
-	 *            exponent to raise to
+	 * @param exponent exponent to raise to
 	 * @return result of exponentiation.
 	 * @since 2019-04-13
 	 * @since v0.2.0
@@ -215,27 +180,27 @@ public final class UnitPrefix {
 	public UnitPrefix toExponent(final double exponent) {
 		return valueOf(Math.pow(this.getMultiplier(), exponent));
 	}
-
+	
 	/**
 	 * @return a string describing the prefix and its multiplier
 	 */
 	@Override
 	public String toString() {
-		if (this.primaryName.isPresent())
-			return String.format("%s (\u00D7 %s)", this.primaryName.get(), this.multiplier);
-		else if (this.symbol.isPresent())
-			return String.format("%s (\u00D7 %s)", this.symbol.get(), this.multiplier);
+		if (this.getPrimaryName().isPresent())
+			return String.format("%s (\u00D7 %s)", this.getPrimaryName().get(),
+					this.multiplier);
+		else if (this.getSymbol().isPresent())
+			return String.format("%s (\u00D7 %s)", this.getSymbol().get(),
+					this.multiplier);
 		else
 			return String.format("Unit Prefix (\u00D7 %s)", this.multiplier);
 	}
-
+	
 	/**
-	 * @param ns
-	 *            name(s) and symbol to use
+	 * @param ns name(s) and symbol to use
 	 * @return copy of this prefix with provided name(s) and symbol
 	 * @since 2019-11-26
-	 * @throws NullPointerException
-	 *             if ns is null
+	 * @throws NullPointerException if ns is null
 	 */
 	public UnitPrefix withName(final NameSymbol ns) {
 		return valueOf(this.multiplier, ns);
diff --git a/src/main/java/sevenUnitsGUI/Presenter.java b/src/main/java/sevenUnitsGUI/Presenter.java
index b38f90b..5c8ce53 100644
--- a/src/main/java/sevenUnitsGUI/Presenter.java
+++ b/src/main/java/sevenUnitsGUI/Presenter.java
@@ -18,6 +18,7 @@ package sevenUnitsGUI;
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
@@ -50,7 +51,8 @@ import sevenUnits.utils.UncertainDouble;
  */
 public final class Presenter {
 	/** The default place where settings are stored. */
-	private static final String DEFAULT_SETTINGS_FILEPATH = "settings.txt";
+	private static final Path DEFAULT_SETTINGS_FILEPATH = Path
+			.of("settings.txt");
 	/** The default place where units are stored. */
 	private static final String DEFAULT_UNITS_FILEPATH = "/unitsfile.txt";
 	/** The default place where dimensions are stored. */
@@ -406,17 +408,18 @@ public final class Presenter {
 	 * 			
 	 * @since 2022-03-30
 	 */
-	public boolean isOneWayConversionEnabled() {
+	public boolean oneWayConversionEnabled() {
 		return this.oneWayConversionEnabled;
 	}
 	
 	/**
 	 * Loads settings from the user's settings file and applies them to the
 	 * presenter.
-	 * 
+	 *
+	 * @param settingsFile file settings should be loaded from
 	 * @since 2021-12-15
 	 */
-	private void loadSettings() {}
+	void loadSettings(Path settingsFile) {}
 	
 	/**
 	 * Completes creation of the presenter. This part of the initialization
@@ -438,9 +441,10 @@ public final class Presenter {
 	/**
 	 * Saves the presenter's settings to the user settings file.
 	 * 
+	 * @param settingsFile file settings should be saved to
 	 * @since 2021-12-15
 	 */
-	private void saveSettings() {}
+	void saveSettings(Path settingsFile) {}
 	
 	/**
 	 * @param numberDisplayRule the new rule that will be used by this presenter
diff --git a/src/main/java/sevenUnitsGUI/StandardDisplayRules.java b/src/main/java/sevenUnitsGUI/StandardDisplayRules.java
index 331f598..f6272c8 100644
--- a/src/main/java/sevenUnitsGUI/StandardDisplayRules.java
+++ b/src/main/java/sevenUnitsGUI/StandardDisplayRules.java
@@ -45,6 +45,32 @@ final class StandardDisplayRules {
 	};
 	
 	/**
+	 * Gets a display rule that rounds numbers to a fixed number of decimal
+	 * places.
+	 *
+	 * @param decimalPlaces number of decimal places
+	 * @return display rule
+	 * @since 2022-04-16
+	 */
+	public static final Function<UncertainDouble, String> getFixedPlacesRule(
+			int decimalPlaces) {
+		throw new UnsupportedOperationException("Not implemented yet");
+	}
+	
+	/**
+	 * Gets a display rule that rounds numbers to a fixed number of significant
+	 * figures.
+	 *
+	 * @param significantFigures number of significant figures
+	 * @return display rule
+	 * @since 2022-04-16
+	 */
+	public static final Function<UncertainDouble, String> getFixedPrecisionRule(
+			int significantFigures) {
+		throw new UnsupportedOperationException("Not implemented yet");
+	}
+	
+	/**
 	 * @return a rule that rounds using UncertainDouble's own toString(false)
 	 *         function.
 	 * @since 2021-12-24
diff --git a/src/main/java/sevenUnitsGUI/ViewBot.java b/src/main/java/sevenUnitsGUI/ViewBot.java
index 9f9a524..988d1bc 100644
--- a/src/main/java/sevenUnitsGUI/ViewBot.java
+++ b/src/main/java/sevenUnitsGUI/ViewBot.java
@@ -25,6 +25,7 @@ import java.util.Set;
 
 import sevenUnits.unit.UnitType;
 import sevenUnits.utils.NameSymbol;
+import sevenUnits.utils.Nameable;
 
 /**
  * A class that simulates a View (supports both unit and expression conversion)
@@ -34,6 +35,163 @@ import sevenUnits.utils.NameSymbol;
  * @since 2022-01-29
  */
 final class ViewBot implements UnitConversionView, ExpressionConversionView {
+	/**
+	 * A record of the parameters given to
+	 * {@link View#showPrefix(NameSymbol, String)}, for testing.
+	 *
+	 * @since 2022-04-16
+	 */
+	public static final class PrefixViewingRecord implements Nameable {
+		private final NameSymbol nameSymbol;
+		private final String multiplierString;
+		
+		/**
+		 * @param nameSymbol
+		 * @param multiplierString
+		 * @since 2022-04-16
+		 */
+		public PrefixViewingRecord(NameSymbol nameSymbol,
+				String multiplierString) {
+			this.nameSymbol = nameSymbol;
+			this.multiplierString = multiplierString;
+		}
+		
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj)
+				return true;
+			if (!(obj instanceof PrefixViewingRecord))
+				return false;
+			final PrefixViewingRecord other = (PrefixViewingRecord) obj;
+			return Objects.equals(this.multiplierString, other.multiplierString)
+					&& Objects.equals(this.nameSymbol, other.nameSymbol);
+		}
+		
+		@Override
+		public NameSymbol getNameSymbol() {
+			return this.nameSymbol;
+		}
+		
+		@Override
+		public int hashCode() {
+			return Objects.hash(this.multiplierString, this.nameSymbol);
+		}
+		
+		public String multiplierString() {
+			return this.multiplierString;
+		}
+		
+		public NameSymbol nameSymbol() {
+			return this.nameSymbol;
+		}
+		
+		@Override
+		public String toString() {
+			final StringBuilder builder = new StringBuilder();
+			builder.append("PrefixViewingRecord [nameSymbol=");
+			builder.append(this.nameSymbol);
+			builder.append(", multiplierString=");
+			builder.append(this.multiplierString);
+			builder.append("]");
+			return builder.toString();
+		}
+	}
+	
+	/**
+	 * A record of the parameters given to
+	 * {@link View#showUnit(NameSymbol, String, String, UnitType)}, for testing.
+	 *
+	 * @since 2022-04-16
+	 */
+	public static final class UnitViewingRecord implements Nameable {
+		private final NameSymbol nameSymbol;
+		private final String definition;
+		private final String dimensionName;
+		private final UnitType unitType;
+		
+		/**
+		 * @since 2022-04-16
+		 */
+		public UnitViewingRecord(NameSymbol nameSymbol, String definition,
+				String dimensionName, UnitType unitType) {
+			this.nameSymbol = nameSymbol;
+			this.definition = definition;
+			this.dimensionName = dimensionName;
+			this.unitType = unitType;
+		}
+		
+		/**
+		 * @return the definition
+		 * @since 2022-04-16
+		 */
+		public String definition() {
+			return this.definition;
+		}
+		
+		/**
+		 * @return the dimensionName
+		 * @since 2022-04-16
+		 */
+		public String dimensionName() {
+			return this.dimensionName;
+		}
+		
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj)
+				return true;
+			if (!(obj instanceof UnitViewingRecord))
+				return false;
+			final UnitViewingRecord other = (UnitViewingRecord) obj;
+			return Objects.equals(this.definition, other.definition)
+					&& Objects.equals(this.dimensionName, other.dimensionName)
+					&& Objects.equals(this.nameSymbol, other.nameSymbol)
+					&& this.unitType == other.unitType;
+		}
+		
+		/**
+		 * @return the nameSymbol
+		 * @since 2022-04-16
+		 */
+		@Override
+		public NameSymbol getNameSymbol() {
+			return this.nameSymbol;
+		}
+		
+		@Override
+		public int hashCode() {
+			return Objects.hash(this.definition, this.dimensionName,
+					this.nameSymbol, this.unitType);
+		}
+		
+		public NameSymbol nameSymbol() {
+			return this.nameSymbol;
+		}
+		
+		@Override
+		public String toString() {
+			final StringBuilder builder = new StringBuilder();
+			builder.append("UnitViewingRecord [nameSymbol=");
+			builder.append(this.nameSymbol);
+			builder.append(", definition=");
+			builder.append(this.definition);
+			builder.append(", dimensionName=");
+			builder.append(this.dimensionName);
+			builder.append(", unitType=");
+			builder.append(this.unitType);
+			builder.append("]");
+			return builder.toString();
+		}
+		
+		/**
+		 * @return the unitType
+		 * @since 2022-04-16
+		 */
+		public UnitType unitType() {
+			return this.unitType;
+		}
+	}
+	
 	/** The presenter that works with this ViewBot */
 	private final Presenter presenter;
 	
@@ -62,6 +220,10 @@ final class ViewBot implements UnitConversionView, ExpressionConversionView {
 	private final List<UnitConversionRecord> unitConversions;
 	/** Saved outputs of all unit expressions */
 	private final List<UnitConversionRecord> expressionConversions;
+	/** Saved outputs of all unit viewings */
+	private final List<UnitViewingRecord> unitViewingRecords;
+	/** Saved outputs of all prefix viewings */
+	private final List<PrefixViewingRecord> prefixViewingRecords;
 	
 	/**
 	 * Creates a new {@code ViewBot} with a new presenter.
@@ -73,6 +235,8 @@ final class ViewBot implements UnitConversionView, ExpressionConversionView {
 		
 		this.unitConversions = new ArrayList<>();
 		this.expressionConversions = new ArrayList<>();
+		this.unitViewingRecords = new ArrayList<>();
+		this.prefixViewingRecords = new ArrayList<>();
 	}
 	
 	/**
@@ -80,7 +244,7 @@ final class ViewBot implements UnitConversionView, ExpressionConversionView {
 	 * @since 2022-04-09
 	 */
 	public List<UnitConversionRecord> expressionConversionList() {
-		return this.expressionConversions;
+		return Collections.unmodifiableList(this.expressionConversions);
 	}
 	
 	/**
@@ -158,6 +322,14 @@ final class ViewBot implements UnitConversionView, ExpressionConversionView {
 		throw new UnsupportedOperationException("Not implemented yet");
 	}
 	
+	/**
+	 * @return list of records of this viewBot's prefix views
+	 * @since 2022-04-16
+	 */
+	public List<PrefixViewingRecord> prefixViewList() {
+		return Collections.unmodifiableList(this.prefixViewingRecords);
+	}
+	
 	@Override
 	public void setDimensionNames(Set<String> dimensionNames) {
 		this.dimensionNames = Objects.requireNonNull(dimensionNames,
@@ -259,6 +431,24 @@ final class ViewBot implements UnitConversionView, ExpressionConversionView {
 		throw new UnsupportedOperationException("Not implemented yet");
 	}
 	
+	public void setViewedPrefixName(
+			@SuppressWarnings("unused") Optional<String> viewedPrefixName) {
+		throw new UnsupportedOperationException("Not implemented yet");
+	}
+	
+	public void setViewedPrefixName(String viewedPrefixName) {
+		this.setViewedPrefixName(Optional.of(viewedPrefixName));
+	}
+	
+	public void setViewedUnitName(
+			@SuppressWarnings("unused") Optional<String> viewedUnitName) {
+		throw new UnsupportedOperationException("Not implemented yet");
+	}
+	
+	public void setViewedUnitName(String viewedUnitName) {
+		this.setViewedUnitName(Optional.of(viewedUnitName));
+	}
+	
 	@Override
 	public void showErrorMessage(String title, String message) {
 		System.err.printf("%s: %s%n", title, message);
@@ -299,4 +489,12 @@ final class ViewBot implements UnitConversionView, ExpressionConversionView {
 	public List<UnitConversionRecord> unitConversionList() {
 		return Collections.unmodifiableList(this.unitConversions);
 	}
+	
+	/**
+	 * @return list of records of unit viewings made by this bot
+	 * @since 2022-04-16
+	 */
+	public List<UnitViewingRecord> unitViewList() {
+		return Collections.unmodifiableList(this.unitViewingRecords);
+	}
 }
diff --git a/src/test/java/sevenUnitsGUI/PresenterTest.java b/src/test/java/sevenUnitsGUI/PresenterTest.java
index 3fe7e47..85ebe09 100644
--- a/src/test/java/sevenUnitsGUI/PresenterTest.java
+++ b/src/test/java/sevenUnitsGUI/PresenterTest.java
@@ -17,20 +17,29 @@
 package sevenUnitsGUI;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assumptions.assumeTrue;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.nio.file.Path;
 import java.util.List;
 import java.util.Set;
+import java.util.function.Function;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
 
 import sevenUnits.unit.BaseDimension;
+import sevenUnits.unit.BritishImperial;
 import sevenUnits.unit.Metric;
 import sevenUnits.unit.Unit;
+import sevenUnits.unit.UnitType;
 import sevenUnits.unit.UnitValue;
+import sevenUnits.utils.NameSymbol;
 import sevenUnits.utils.Nameable;
 import sevenUnits.utils.ObjectProduct;
+import sevenUnits.utils.UncertainDouble;
 
 /**
  * @author Adrien Hopkins
@@ -38,12 +47,27 @@ import sevenUnits.utils.ObjectProduct;
  * @since 2022-02-10
  */
 public final class PresenterTest {
+	private static final Path TEST_SETTINGS = Path.of("src", "test", "resources",
+			"test-settings.txt");
 	static final Set<Unit> testUnits = Set.of(Metric.METRE, Metric.KILOMETRE,
 			Metric.METRE_PER_SECOND, Metric.KILOMETRE_PER_HOUR);
 	
 	static final Set<ObjectProduct<BaseDimension>> testDimensions = Set
 			.of(Metric.Dimensions.LENGTH, Metric.Dimensions.VELOCITY);
 	
+	/**
+	 * @return rounding rules used by {@link #testRoundingRules}
+	 * @since 2022-04-16
+	 */
+	private static final Stream<Function<UncertainDouble, String>> getRoundingRules() {
+		final var SCIENTIFIC_ROUNDING = StandardDisplayRules.getScientificRule();
+		final var INTEGER_ROUNDING = StandardDisplayRules.getFixedPlacesRule(0);
+		final var SIG_FIG_ROUNDING = StandardDisplayRules
+				.getFixedPrecisionRule(4);
+		
+		return Stream.of(SCIENTIFIC_ROUNDING, INTEGER_ROUNDING, SIG_FIG_ROUNDING);
+	}
+	
 	private static final Set<String> names(Set<? extends Nameable> units) {
 		return units.stream().map(Nameable::getName).collect(Collectors.toSet());
 	}
@@ -106,23 +130,185 @@ public final class PresenterTest {
 		assertEquals(List.of(expectedUC), viewBot.unitConversionList());
 	}
 	
+	/**
+	 * Tests that duplicate units are successfully removed, if that is asked for
+	 * 
+	 * @since 2022-04-16
+	 */
 	@Test
 	void testDuplicateUnits() {
-		assumeTrue(false, "Not yet implemented");
-		/*
-		 * enable and disable duplicate units and check for those in From and To,
-		 * include duplicate units in the input set
-		 */
+		final var metre = Metric.METRE;
+		final var meter = Metric.METRE.withName(NameSymbol.of("meter", "m"));
+		
+		// load 2 duplicate units
+		final var viewBot = new ViewBot();
+		final var presenter = new Presenter(viewBot);
+		presenter.database.clear();
+		presenter.database.addUnit("metre", metre);
+		presenter.database.addUnit("meter", meter);
+		
+		// test that only one of them is included if duplicate units disabled
+		presenter.setShowDuplicateUnits(false);
+		presenter.updateView();
+		assertEquals(1, viewBot.getFromUnitNames().size());
+		assertEquals(1, viewBot.getToUnitNames().size());
+		
+		// test that both of them is included if duplicate units enabled
+		presenter.setShowDuplicateUnits(true);
+		presenter.updateView();
+		assertEquals(2, viewBot.getFromUnitNames().size());
+		assertEquals(2, viewBot.getToUnitNames().size());
 	}
 	
+	/**
+	 * Tests that one-way conversion correctly filters From and To units
+	 * 
+	 * @since 2022-04-16
+	 */
 	@Test
 	void testOneWayConversion() {
-		assumeTrue(false, "Not yet implemented");
-		/*
-		 * enable and disable one-way conversion, testing the units in From and To
-		 * on each setting to ensure they match the rule. Include at least one
-		 * metric exception.
-		 */
+		// metre is metric, inch is non-metric, tempC is semi-metric
+		final var allNames = Set.of("metre", "inch", "tempC");
+		final var metricNames = Set.of("metre", "tempC");
+		final var nonMetricNames = Set.of("inch", "tempC");
+		
+		// load view with one metric and one non-metric unit
+		final var viewBot = new ViewBot();
+		final var presenter = new Presenter(viewBot);
+		presenter.database.clear();
+		presenter.database.addUnit("metre", Metric.METRE);
+		presenter.database.addUnit("inch", BritishImperial.Length.INCH);
+		presenter.database.addUnit("tempC", Metric.CELSIUS);
+		
+		// test that units are removed from each side when one-way conversion is
+		// enabled
+		presenter.setOneWayConversionEnabled(true);
+		presenter.updateView();
+		assertEquals(metricNames, viewBot.getFromUnitNames());
+		assertEquals(nonMetricNames, viewBot.getToUnitNames());
+		
+		// test that units are kept when one-way conversion is disabled
+		presenter.setOneWayConversionEnabled(false);
+		presenter.updateView();
+		assertEquals(allNames, viewBot.getFromUnitNames());
+		assertEquals(allNames, viewBot.getToUnitNames());
+	}
+	
+	/**
+	 * Tests the prefix-viewing functionality.
+	 * 
+	 * @since 2022-04-16
+	 */
+	@Test
+	void testPrefixViewing() {
+		// setup
+		final var viewBot = new ViewBot();
+		final var presenter = new Presenter(viewBot);
+		viewBot.setViewablePrefixNames(Set.of("kilo", "milli"));
+		presenter.setNumberDisplayRule(UncertainDouble::toString);
+		
+		// view prefix
+		viewBot.setViewedPrefixName("kilo");
+		presenter.prefixSelected(); // just in case
+		
+		// get correct values
+		final var expectedNameSymbol = Metric.KILO.getNameSymbol();
+		final var expectedMultiplierString = String
+				.valueOf(Metric.KILO.getMultiplier());
+		
+		// test that presenter's values are correct
+		final var prefixRecord = viewBot.prefixViewList().get(0);
+		assertEquals(expectedNameSymbol, prefixRecord.getNameSymbol());
+		assertEquals(expectedMultiplierString, prefixRecord.multiplierString());
+	}
+	
+	/**
+	 * Tests that rounding rules are used correctly.
+	 * 
+	 * @since 2022-04-16
+	 */
+	@ParameterizedTest
+	@MethodSource("getRoundingRules")
+	void testRoundingRules(Function<UncertainDouble, String> roundingRule) {
+		// setup
+		final var viewBot = new ViewBot();
+		final var presenter = new Presenter(viewBot);
+		presenter.setNumberDisplayRule(roundingRule);
+		
+		// convert and round
+		viewBot.setInputValue("12345.6789");
+		viewBot.setFromSelection("metre");
+		viewBot.setToSelection("kilometre");
+		presenter.convertUnits();
+		
+		// test the result of the rounding
+		final String expectedOutputString = roundingRule
+				.apply(UncertainDouble.of(12.3456789, 0));
+		final String actualOutputString = viewBot.unitConversionList().get(0)
+				.outputValueString();
+		assertEquals(expectedOutputString, actualOutputString);
+	}
+	
+	/**
+	 * Tests that settings can be saved to and loaded from a file.
+	 * 
+	 * @since 2022-04-16
+	 */
+	@Test
+	void testSettingsSaving() {
+		// setup
+		final var viewBot = new ViewBot();
+		final var presenter = new Presenter(viewBot);
+		
+		// set and save custom settings
+		presenter.setOneWayConversionEnabled(true);
+		presenter.setShowDuplicateUnits(true);
+		presenter.setNumberDisplayRule(
+				StandardDisplayRules.getFixedPrecisionRule(11));
+		presenter.saveSettings(TEST_SETTINGS);
+		
+		// overwrite custom settings
+		presenter.setOneWayConversionEnabled(false);
+		presenter.setShowDuplicateUnits(false);
+		presenter.setNumberDisplayRule(StandardDisplayRules.getScientificRule());
+		
+		// load settings & test that they're the same
+		presenter.loadSettings(TEST_SETTINGS);
+		assertTrue(presenter.oneWayConversionEnabled());
+		assertTrue(presenter.duplicateUnitsShown());
+		assertEquals(StandardDisplayRules.getFixedPlacesRule(11),
+				presenter.getNumberDisplayRule());
+	}
+	
+	/**
+	 * Ensures the Presenter generates the correct data upon a unit-viewing.
+	 * 
+	 * @since 2022-04-16
+	 */
+	@Test
+	void testUnitViewing() {
+		// setup
+		final var viewBot = new ViewBot();
+		final var presenter = new Presenter(viewBot);
+		viewBot.setViewableUnitNames(names(testUnits));
+		
+		// view unit
+		viewBot.setViewedUnitName("metre");
+		presenter.unitNameSelected(); // just in case this isn't triggered
+												// automatically
+		
+		// get correct values
+		final var expectedNameSymbol = Metric.METRE.getNameSymbol();
+		final var expectedDefinition = Metric.METRE.toDefinitionString();
+		final var expectedDimensionName = Metric.METRE.getDimension().getName();
+		final var expectedUnitType = UnitType.METRIC;
+		
+		// test for correctness
+		final var viewRecord = viewBot.unitViewList().get(0);
+		assertEquals(expectedNameSymbol, viewRecord.getNameSymbol());
+		assertEquals(expectedDefinition, viewRecord.definition());
+		assertEquals(expectedDimensionName, viewRecord.dimensionName());
+		assertEquals(expectedUnitType, viewRecord.unitType());
 	}
 	
 	/**