diff --git a/src/main/kotlin/VerifierCli.kt b/src/main/kotlin/VerifierCli.kt
index 7f9a991..6d151ba 100644
--- a/src/main/kotlin/VerifierCli.kt
+++ b/src/main/kotlin/VerifierCli.kt
@@ -19,15 +19,16 @@ package com.android.keyattestation.verifier
 import java.io.File
 import java.io.PrintStream
 import java.security.cert.X509Certificate
+import java.time.Instant
 
 // Any chain shorter than this is not possibly valid Key Attestation chain.
 private const val MIN_CERTS_IN_VALID_CHAIN = 3
 
-class VerifierCli(private val output: PrintStream) {
+class VerifierCli(private val output: PrintStream, private val instantSource: InstantSource) {
   companion object {
     @JvmStatic
     fun main(args: Array<String>) {
-      VerifierCli(System.out).run(args)
+      VerifierCli(System.out, { Instant.now() }).run(args)
     }
   }
 
@@ -62,7 +63,7 @@ class VerifierCli(private val output: PrintStream) {
       Verifier(
         trustAnchorsSource = GoogleTrustAnchors,
         revokedSerialsSource = { emptySet() },
-        instantSource = { java.time.Instant.now() },
+        instantSource,
       )
 
     val result = verifier.verify(certs)
diff --git a/src/test/kotlin/VerifierCliTest.kt b/src/test/kotlin/VerifierCliTest.kt
index e161166..06002e1 100644
--- a/src/test/kotlin/VerifierCliTest.kt
+++ b/src/test/kotlin/VerifierCliTest.kt
@@ -22,6 +22,8 @@ import java.io.ByteArrayOutputStream
 import java.io.PrintStream
 import java.nio.charset.StandardCharsets
 import java.nio.file.Files
+import java.nio.file.Path
+import java.time.Instant
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
@@ -29,17 +31,39 @@ import org.junit.runners.JUnit4
 @RunWith(JUnit4::class)
 class VerifierCliTest {
   companion object {
+    // For tests have no time dependency
+    val INCONSEQUENTIAL_TIME = Instant.EPOCH
+
     private fun resolveTestData(path: String) =
     kotlin.io.path.Path("testdata/$path")
+
+    private fun getValidTimeFromCert(path: Path): Instant {
+      val pem = Files.readString(path)
+      val certs =
+        """-----BEGIN CERTIFICATE-----([\s\S]*?)-----END CERTIFICATE-----"""
+          .toRegex()
+          .findAll(pem)
+          .map { it.value.asX509Certificate() }
+          .toList()
+
+      check(certs.size >= 2) { "Certificate chain must have at least 2 certificates" }
+      val intermediate = certs[1]
+      val notBefore = intermediate.notBefore.toInstant()
+      val notAfter = intermediate.notAfter.toInstant()
+
+      // Return a time in the middle of the validity period.
+      return notBefore.plusMillis((notAfter.toEpochMilli() - notBefore.toEpochMilli()) / 2)
+    }
   }
 
   @Test
   fun run_validChain_outputsSuccess() {
     val path = resolveTestData("tegu/sdk36/TEE_EC_2026_ROOT.pem")
+    val validTime = getValidTimeFromCert(path)
     val outputStream = ByteArrayOutputStream()
     val printStream = PrintStream(outputStream, true, StandardCharsets.UTF_8.name())
 
-    VerifierCli(printStream).run(arrayOf(path.toString()))
+    VerifierCli(printStream, { validTime }).run(arrayOf(path.toString()))
 
     val output = outputStream.toString(StandardCharsets.UTF_8.name())
     assertThat(output).contains("Verification Successful!")
@@ -50,10 +74,11 @@ class VerifierCliTest {
   @Test
   fun run_invalidChain_outputsFailure() {
     val path = resolveTestData("invalid/tags_not_in_ascending_order.pem")
+    val validTime = getValidTimeFromCert(path)
     val outputStream = ByteArrayOutputStream()
     val printStream = PrintStream(outputStream, true, StandardCharsets.UTF_8.name())
 
-    VerifierCli(printStream).run(arrayOf(path.toString()))
+    VerifierCli(printStream, { validTime }).run(arrayOf(path.toString()))
 
     val output = outputStream.toString(StandardCharsets.UTF_8.name())
     assertThat(output).contains("Verification Failed")
@@ -66,7 +91,7 @@ class VerifierCliTest {
     val outputStream = ByteArrayOutputStream()
     val printStream = PrintStream(outputStream, true, StandardCharsets.UTF_8.name())
 
-    VerifierCli(printStream).run(arrayOf(path.toString()))
+    VerifierCli(printStream, { INCONSEQUENTIAL_TIME }).run(arrayOf(path.toString()))
 
     val output = outputStream.toString(StandardCharsets.UTF_8.name())
     assertThat(output).contains("No certificates found in the file.")
@@ -101,7 +126,7 @@ F3amnfzZkTIFYCL1rPPb6Vp9pI1xhRE5Uk21Eso=
     val outputStream = ByteArrayOutputStream()
     val printStream = PrintStream(outputStream, true, StandardCharsets.UTF_8.name())
 
-    VerifierCli(printStream).run(arrayOf(path.toString()))
+    VerifierCli(printStream, { INCONSEQUENTIAL_TIME }).run(arrayOf(path.toString()))
 
     val output = outputStream.toString(StandardCharsets.UTF_8.name())
     assertThat(output)
@@ -154,7 +179,7 @@ ykrM9WmORlkUk9NsoQ==
     val outputStream = ByteArrayOutputStream()
     val printStream = PrintStream(outputStream, true, StandardCharsets.UTF_8.name())
 
-    VerifierCli(printStream).run(arrayOf(path.toString()))
+    VerifierCli(printStream, { INCONSEQUENTIAL_TIME }).run(arrayOf(path.toString()))
 
     val output = outputStream.toString(StandardCharsets.UTF_8.name())
     assertThat(output).contains("Less than 3 certificates found in the file.")