Added a test for evaluating an expression & fixed a bug it found

The bug: non-exact LinearUnitValue instances have their value printed as "(",
i.e. "(5.0 ± 0.1) m" will be printed as "( m"

2 files changed, 33 insertions, 6 deletions

diff --git a/src/main/java/sevenUnits/unit/LinearUnitValue.java b/src/main/java/sevenUnits/unit/LinearUnitValue.java
index a36d568..2219ffd 100644
--- a/src/main/java/sevenUnits/unit/LinearUnitValue.java
+++ b/src/main/java/sevenUnits/unit/LinearUnitValue.java
@@ -324,12 +324,12 @@ public final class LinearUnitValue {
 		
 		// get rounded strings
 		// if showUncertainty is true, add brackets around the string
-		final String valueString = showUncertainty ? "("
-				: "" + this.value.toString(showUncertainty)
-						+ (showUncertainty ? ")" : "");
-		final String baseValueString = showUncertainty ? "("
-				: "" + baseValue.toString(showUncertainty)
-						+ (showUncertainty ? ")" : "");
+		final String valueString = (showUncertainty ? "(" : "")
+				+ this.value.toString(showUncertainty)
+				+ (showUncertainty ? ")" : "");
+		final String baseValueString = (showUncertainty ? "(" : "")
+				+ baseValue.toString(showUncertainty)
+				+ (showUncertainty ? ")" : "");
 		
 		// create string
 		if (primaryName.isEmpty() && symbol.isEmpty())
diff --git a/src/test/java/sevenUnits/unit/UnitDatabaseTest.java b/src/test/java/sevenUnits/unit/UnitDatabaseTest.java
index 31323a7..7612fc5 100644
--- a/src/test/java/sevenUnits/unit/UnitDatabaseTest.java
+++ b/src/test/java/sevenUnits/unit/UnitDatabaseTest.java
@@ -36,6 +36,8 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
+import sevenUnits.utils.UncertainDouble;
+
 /**
  * A test for the {@link UnitDatabase} class. This is NOT part of this program's
  * public API.
@@ -88,6 +90,31 @@ class UnitDatabaseTest {
 	}
 	
 	/**
+	 * A test for the {@link UnitDatabase#evaluateUnitExpression(String)}
+	 * function. Simple because the expression parser has its own test.
+	 * 
+	 * @since 2021-09-27
+	 */
+	@Test
+	public void testEvaluateExpression() {
+		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 LinearUnitValue expected = LinearUnitValue.of(J,
+				UncertainDouble.of(12, Math.sqrt(14.625)));
+		// note: units are exact, each number has an uncertainty of 1
+		final LinearUnitValue actual = database
+				.evaluateUnitExpression("J + (2 * 3) J + (20 / 4) J");
+		assertEquals(expected, actual);
+	}
+	
+	/**
 	 * Confirms that operations that shouldn't function for infinite databases
 	 * throw an {@code IllegalStateException}.
 	 *