diff --git a/src/prisms.ts b/src/prisms.ts
index c2b4e3d..c700b85 100644
--- a/src/prisms.ts
+++ b/src/prisms.ts
@@ -2,16 +2,13 @@ import { AbstractPrism, Prism } from "./types.ts";
 
 /**
  * Static methods for prisms
- *
  */
 export class Prisms {
-
   /**
    * Construct a prism that unions a series of prisms.
    *
    * - view: returns the first non-null view of the prism series
    * - set: sets the value of the first prism that has a non-null view
-   *
    */
   static union<Whole, Part>(...prisms: Prism<Whole, Part>[]) {
     return new class extends AbstractPrism<Whole, Part> {
diff --git a/src/traversals.test.ts b/src/traversals.test.ts
new file mode 100644
index 0000000..c166719
--- /dev/null
+++ b/src/traversals.test.ts
@@ -0,0 +1,49 @@
+import * as Peach from "../../peach.ts/src/mod.ts";
+import * as SubEdit from "./mod.ts";
+import { assertEquals } from "https://deno.land/std@0.171.0/testing/asserts.ts";
+
+import { Traversals } from "./traversals.ts";
+
+const sampleText = Peach.String.from(
+  Peach.String.blocks.myanmarExtendedA(Peach.Number.uniform),
+  Peach.Number.uniform(0, 100),
+);
+
+Deno.test({
+  name: "Traversals.union.view: union() == []",
+  fn() {
+    const unioned = Traversals.union();
+
+    for (const tcase of Peach.Array.from(sampleText, 100)()) {
+      assertEquals(unioned.view(tcase), []);
+    }
+  },
+});
+
+Deno.test({
+  name: "Traversals.union.view: union(traversal) ~ traversal",
+  fn() {
+    const traversal = SubEdit.EachMatch(/.{3}/gd);
+    const unioned = Traversals.union(traversal);
+
+    for (const tcase of Peach.Array.from(sampleText, 100)()) {
+      assertEquals(unioned.view(tcase), traversal.view(tcase));
+    }
+  },
+});
+
+Deno.test({
+  name:
+    "Traversals.union.view: union(traversal, traversal) ~ traversal + traversal",
+  fn() {
+    const traversal = SubEdit.EachMatch(/.{3}/gd);
+    const unioned = Traversals.union(traversal, traversal);
+
+    for (const tcase of Peach.Array.from(sampleText, 100)()) {
+      assertEquals(
+        unioned.view(tcase),
+        traversal.view(tcase).concat(traversal.view(tcase)),
+      );
+    }
+  },
+});
diff --git a/src/traversals.ts b/src/traversals.ts
index 7dc18e9..871b022 100644
--- a/src/traversals.ts
+++ b/src/traversals.ts
@@ -2,16 +2,13 @@ import { AbstractTraversal, Traversal } from "./types.ts";
 
 /**
  * Static methods for traversals
- *
  */
 export class Traversals {
-
   /**
    * Construct a traversal that joins the views of multiple traversals.
    *
    * - view: returns the concatenation of the views of each traversal
    * - modify: applies the modifier to the view of each traversal
-   *
    */
   static union<Whole, Part>(...traversals: Traversal<Whole, Part>[]) {
     return new class extends AbstractTraversal<Whole, Part> {
diff --git a/src/types.ts b/src/types.ts
index 47ad7ef..b25efaa 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -14,7 +14,6 @@ export interface Prism<Whole, Part> {
 
 /*
  * Partial implementation of the prism interface, leaving view and set abstract
- *
  */
 export abstract class AbstractPrism<Whole, Part> implements Prism<Whole, Part> {
   abstract view(whole: Whole): Part | null;
@@ -84,7 +83,6 @@ export interface Traversal<Whole, Part> {
 
 /*
  * Partial implementation of the traversal interface, leaving view and modify abstract
- *
  */
 export abstract class AbstractTraversal<Whole, Part>
   implements Traversal<Whole, Part> {