diff --git a/WalletSdk/build.gradle.kts b/WalletSdk/build.gradle.kts
index d187615..cb66bfb 100644
--- a/WalletSdk/build.gradle.kts
+++ b/WalletSdk/build.gradle.kts
@@ -128,6 +128,7 @@ dependencies {
     implementation("androidx.camera:camera-view:1.3.2")
     implementation("com.google.zxing:core:3.3.3")
     implementation("com.google.accompanist:accompanist-permissions:0.34.0")
+    implementation("androidx.test.ext:junit-ktx:1.1.5")
     /* End UI dependencies */
     testImplementation("junit:junit:4.13.2")
     testImplementation("org.robolectric:robolectric:4.8")
diff --git a/WalletSdk/src/main/java/com/spruceid/wallet/sdk/KeyManager.kt b/WalletSdk/src/main/java/com/spruceid/wallet/sdk/KeyManager.kt
index b9bc714..1f522c8 100644
--- a/WalletSdk/src/main/java/com/spruceid/wallet/sdk/KeyManager.kt
+++ b/WalletSdk/src/main/java/com/spruceid/wallet/sdk/KeyManager.kt
@@ -26,8 +26,7 @@ class KeyManager {
      * Returns the Android Keystore.
      * @return instance of the key store.
      */
-    @VisibleForTesting
-    fun getKeyStore(): KeyStore {
+    private fun getKeyStore(): KeyStore {
         return KeyStore.getInstance("AndroidKeyStore").apply {
             load(null)
         }
@@ -139,7 +138,7 @@ class KeyManager {
      * @property input byte array to be processed.
      * @return byte array with 32 bytes.
      */
-    private fun clampOrFill(input: ByteArray): ByteArray {
+    fun clampOrFill(input: ByteArray): ByteArray {
         return if (input.size > 32) {
             input.drop(1).toByteArray()
         } else if (input.size < 32) {
diff --git a/WalletSdk/src/test/java/com/spruceid/wallet/sdk/ExampleInstrumentedTest.kt b/WalletSdk/src/test/java/com/spruceid/wallet/sdk/ExampleInstrumentedTest.kt
index 657235d..a803d5e 100644
--- a/WalletSdk/src/test/java/com/spruceid/wallet/sdk/ExampleInstrumentedTest.kt
+++ b/WalletSdk/src/test/java/com/spruceid/wallet/sdk/ExampleInstrumentedTest.kt
@@ -1,7 +1,7 @@
 package com.spruceid.wallet.sdk
 
 import androidx.test.InstrumentationRegistry
-import androidx.test.runner.AndroidJUnit4
+import androidx.test.ext.junit.runners.AndroidJUnit4
 
 import org.junit.Test
 import org.junit.runner.RunWith
diff --git a/WalletSdk/src/test/java/com/spruceid/wallet/sdk/KeyManagerTest.kt b/WalletSdk/src/test/java/com/spruceid/wallet/sdk/KeyManagerTest.kt
index 4fcac2c..c9e443c 100644
--- a/WalletSdk/src/test/java/com/spruceid/wallet/sdk/KeyManagerTest.kt
+++ b/WalletSdk/src/test/java/com/spruceid/wallet/sdk/KeyManagerTest.kt
@@ -1,61 +1,38 @@
 package com.spruceid.wallet.sdk
 
-import org.junit.Assert
 import org.junit.Test
 
 import org.junit.Assert.*
-import org.junit.runner.RunWith
-
-import org.robolectric.RobolectricTestRunner
-import org.robolectric.annotation.Config
 
 /**
  * Example local unit test, which will execute on the development machine (host).
  *
  * See [testing documentation](http://d.android.com/tools/testing).
  */
-//@RunWith(RobolectricTestRunner::class)
-//@Config(sdk = [30])
 class KeyManagerTest {
 
     @Test
-    fun getKeyStore() {
+    fun clampOrFill() {
         val keyManager = KeyManager()
-        val keyStore = keyManager.getKeyStore()
-
-        assertNotNull(keyStore)
-    }
-
-    @Test
-    fun reset() {
-        Assert.assertEquals(4, 2 + 2)
-    }
 
-    @Test
-    fun generateSigningKey() {
-    }
-
-    @Test
-    fun getJwk() {
-    }
+        // Greater than 32
+        val inputMoreThan = ByteArray(33) { it.toByte() }
+        val expectedMoreThan = inputMoreThan.drop(1).toByteArray()
+        val resultMoreThan = keyManager.clampOrFill(inputMoreThan)
 
-    @Test
-    fun keyExists() {
-    }
+        assertArrayEquals(expectedMoreThan, resultMoreThan)
 
-    @Test
-    fun signPayload() {
-    }
+        // Less than 32.
+        val inputLessThan = ByteArray(30) { it.toByte() }
+        val expectedLessThan = ByteArray(2) { 0.toByte() } + inputLessThan
+        val result = keyManager.clampOrFill(inputLessThan)
 
-    @Test
-    fun generateEncryptionKey() {
-    }
+        assertArrayEquals(expectedLessThan, result)
 
-    @Test
-    fun encryptPayload() {
-    }
+        // Equal to 32.
+        val inputEqualTo = ByteArray(32) { it.toByte() }
+        val resultEqualTo = keyManager.clampOrFill(inputEqualTo)
 
-    @Test
-    fun decryptPayload() {
+        assertArrayEquals(inputEqualTo, resultEqualTo)
     }
 }