diff --git a/src/index.ts b/src/index.ts
index 7fe6596..fc7f73f 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -22,8 +22,15 @@ export function getPrioritizedHashAlgorithm(
   b: HashAlgorithm,
 ): PrioritizedHashAlgorithm {
   if (a === b) return "";
-  if (!(a in supportedHashAlgorithms)) return "";
-  if (!(b in supportedHashAlgorithms)) return "";
+
+  if (!(a in supportedHashAlgorithms)) {
+    return b in supportedHashAlgorithms ? b : "";
+  }
+
+  if (!(b in supportedHashAlgorithms)) {
+    return a in supportedHashAlgorithms ? a : "";
+  }
+
   return a < b ? b : a;
 }
 
diff --git a/test/get-prioritized-hash-algorithm.js b/test/get-prioritized-hash-algorithm.js
index a09e2d7..8fa4545 100644
--- a/test/get-prioritized-hash-algorithm.js
+++ b/test/get-prioritized-hash-algorithm.js
@@ -14,21 +14,14 @@ test("if both hash algorithms are not supported, return the empty string", funct
   assert.strictEqual(getPrioritizedHashAlgorithm("md5", "sha1"), "");
 });
 
-test.todo(
-  "if one of the hash algorithms is unsupported, return the supported hash algorithm",
-  function () {
-    assert.strictEqual(getPrioritizedHashAlgorithm("md5", "sha256"), "sha256");
-  },
-);
+test("if one of the hash algorithms is unsupported, return the supported hash algorithm", function () {
+  assert.strictEqual(getPrioritizedHashAlgorithm("md5", "sha256"), "sha256");
+});
 
 test("if both strings are empty, return the empty string", function () {
   assert.strictEqual(getPrioritizedHashAlgorithm("", ""), "");
 });
 
-test,
-  todo(
-    "if either is an empty string, it return the supported hash algorithm",
-    function () {
-      assert.strictEqual(getPrioritizedHashAlgorithm("sha256", ""), "sha256");
-    },
-  );
+test("if either is an empty string, it return the supported hash algorithm", function () {
+  assert.strictEqual(getPrioritizedHashAlgorithm("sha256", ""), "sha256");
+});