diff --git a/src/test/java/gov/usgs/earthquake/nshmp/data/SequencesTests.java b/src/test/java/gov/usgs/earthquake/nshmp/data/SequencesTests.java
index 5f2c3721ca720d39909b9b03e0db2063417f270c..975d9755af4a9a805526bb360db339a85b10b6d3 100644
--- a/src/test/java/gov/usgs/earthquake/nshmp/data/SequencesTests.java
+++ b/src/test/java/gov/usgs/earthquake/nshmp/data/SequencesTests.java
@@ -14,32 +14,38 @@ import com.google.common.collect.ImmutableList;
 
 class SequencesTests {
 
-  private static final double[] xs1 = new double[] { 0, 1, 2, 3 };
-  private static final double[] xs2 = new double[] { 1, 2, 3, 4 };
-  private static final double[] xs3 = new double[] { 5, 6, 7 };
-
-  private static final double[] ys1 = new double[] { 10, 9, 8, 7 };
-  private static final double[] ys2 = new double[] { 5, 4, 3, 2 };
-  private static final double[] ys3 = new double[] { 10, 9, 8 };
-
-  private static final XySequence xyBase = XySequence.create(xs1, ys1);
-  private static final XySequence xySameXs = XySequence.create(xs1, ys2);
-  private static final XySequence xyDifferentXs = XySequence.create(xs2, ys2);
-  private static final XySequence xyShorter = XySequence.create(xs3, ys3);
+  private static final XySequence xyBase;
+  private static final XySequence xySameXs;
+  private static final XySequence xyDifferentXs;
+  private static final XySequence xyShorter;
 
   private static final List<XySequence> emptyCollection;
   private static final List<XySequence> singleSequence;
-  private static final XySequence expectedSingleSequenceResults;
   private static final List<XySequence> identicalSequences;
-  private static final XySequence expectedIdenticalSequences;
   private static final List<XySequence> sameXs;
-  private static final XySequence expectedSameXs;
   private static final List<XySequence> differentXs;
-  private static final XySequence expectedDifferentXs;
   private static final List<XySequence> withShorterXs;
+
+  private static final XySequence expectedSingleSequenceResults;
+  private static final XySequence expectedIdenticalSequences;
+  private static final XySequence expectedSameXs;
+  private static final XySequence expectedDifferentXs;
   private static final XySequence expectedWithShorterXs;
 
   static {
+    double[] xs1 = new double[] { 0, 1, 2, 3 };
+    double[] xs2 = new double[] { 1, 2, 3, 4 };
+    double[] xs3 = new double[] { 5, 6, 7 };
+
+    double[] ys1 = new double[] { 10, 9, 8, 7 };
+    double[] ys2 = new double[] { 5, 4, 3, 2 };
+    double[] ys3 = new double[] { 10, 9, 8 };
+
+    xyBase = XySequence.create(xs1, ys1);
+    xySameXs = XySequence.create(xs1, ys2);
+    xyDifferentXs = XySequence.create(xs2, ys2);
+    xyShorter = XySequence.create(xs3, ys3);
+
     emptyCollection = new ImmutableList.Builder<XySequence>().build();
 
     singleSequence = new ImmutableList.Builder<XySequence>()
@@ -47,6 +53,7 @@ class SequencesTests {
         .build();
     expectedSingleSequenceResults = xyBase;
 
+    // add two copies of the same sequence
     identicalSequences = new ImmutableList.Builder<XySequence>()
         .add(xyBase)
         .add(xyBase)
@@ -55,6 +62,7 @@ class SequencesTests {
     Arrays.setAll(result, i -> ys1[i] + ys1[i]);
     expectedIdenticalSequences = XySequence.create(xs1, result);
 
+    // sequences with the same x-values (similar)
     sameXs = new ImmutableList.Builder<XySequence>()
         .add(xyBase)
         .add(xySameXs)
@@ -62,6 +70,7 @@ class SequencesTests {
     Arrays.setAll(result, i -> ys1[i] + ys2[i]);
     expectedSameXs = XySequence.create(xs1, result);
 
+    // sequences with different x-values
     differentXs = new ImmutableList.Builder<XySequence>()
         .add(xyBase)
         .add(xyDifferentXs)
@@ -71,6 +80,7 @@ class SequencesTests {
         new double[] { 0, 1, 2, 3, 4 },
         new double[] { 10, 14, 12, 10, 2 });
 
+    // sequences with different x-values and different length
     withShorterXs = new ImmutableList.Builder<XySequence>()
         .add(xyBase)
         .add(xyDifferentXs)