Refactor `format-common` module (#2196)

* fix: touch up `PasswordEntryTest` KDoc

* feat: add format-common-impl module

* refactor: switch app to format-common-impl

* refactor: move `format-common` tests to `format-common-impl`

* feat: add a test for Steam OTP

2 files changed, 201 insertions, 0 deletions

diff --git a/format-common-impl/src/test/kotlin/app/passwordstore/util/time/TestUserClock.kt b/format-common-impl/src/test/kotlin/app/passwordstore/util/time/TestUserClock.kt
new file mode 100644
index 00000000..8a860a39
--- /dev/null
+++ b/format-common-impl/src/test/kotlin/app/passwordstore/util/time/TestUserClock.kt
@@ -0,0 +1,33 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package app.passwordstore.util.time
+
+import java.time.Clock
+import java.time.Instant
+import java.time.ZoneId
+import java.time.ZoneOffset.UTC
+
+/**
+ * Implementation of [UserClock] that is fixed to [Instant.EPOCH] for deterministic time-based tests
+ */
+class TestUserClock(instant: Instant) : UserClock() {
+
+  constructor() : this(Instant.EPOCH)
+
+  private var clock = fixed(instant, UTC)
+
+  override fun withZone(zone: ZoneId): Clock = clock.withZone(zone)
+
+  override fun getZone(): ZoneId = UTC
+
+  override fun instant(): Instant = clock.instant()
+
+  companion object {
+    fun withAddedSeconds(secondsToAdd: Long): TestUserClock {
+      return TestUserClock(Instant.EPOCH.plusSeconds(secondsToAdd))
+    }
+  }
+}
diff --git a/format-common-impl/src/test/kotlin/app/passwordstore/util/totp/OtpTest.kt b/format-common-impl/src/test/kotlin/app/passwordstore/util/totp/OtpTest.kt
new file mode 100644
index 00000000..54ac492d
--- /dev/null
+++ b/format-common-impl/src/test/kotlin/app/passwordstore/util/totp/OtpTest.kt
@@ -0,0 +1,168 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package app.passwordstore.util.totp
+
+import com.github.michaelbull.result.get
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+import kotlin.test.assertNull
+
+class OtpTest {
+
+  private fun generateOtp(
+    counter: Long,
+    secret: String = "JBSWY3DPEHPK3PXP",
+    algorithm: String = "SHA1",
+    digits: String = "6",
+    issuer: String? = null,
+  ): String? {
+    return Otp.calculateCode(secret, counter, algorithm, digits, issuer).get()
+  }
+
+  @Test
+  fun otpGeneration6Digits() {
+    assertEquals(
+      "953550",
+      generateOtp(
+        counter = 1593333298159 / (1000 * 30),
+      )
+    )
+    assertEquals(
+      "275379",
+      generateOtp(
+        counter = 1593333571918 / (1000 * 30),
+      )
+    )
+    assertEquals(
+      "867507",
+      generateOtp(
+        counter = 1593333600517 / (1000 * 57),
+      )
+    )
+  }
+
+  @Test
+  fun otpGeneration10Digits() {
+    assertEquals(
+      "0740900914",
+      generateOtp(
+        counter = 1593333655044 / (1000 * 30),
+        digits = "10",
+      )
+    )
+    assertEquals(
+      "0070632029",
+      generateOtp(
+        counter = 1593333691405 / (1000 * 30),
+        digits = "10",
+      )
+    )
+    assertEquals(
+      "1017265882",
+      generateOtp(
+        counter = 1593333728893 / (1000 * 83),
+        digits = "10",
+      )
+    )
+  }
+
+  @Test
+  fun otpGenerationIllegalInput() {
+    assertNull(
+      generateOtp(
+        counter = 10000,
+        algorithm = "SHA0",
+        digits = "10",
+      )
+    )
+    assertNull(
+      generateOtp(
+        counter = 10000,
+        digits = "a",
+      )
+    )
+    assertNull(
+      generateOtp(
+        counter = 10000,
+        algorithm = "SHA1",
+        digits = "5",
+      )
+    )
+    assertNull(
+      generateOtp(
+        counter = 10000,
+        digits = "11",
+      )
+    )
+    assertNull(
+      generateOtp(
+        counter = 10000,
+        secret = "JBSWY3DPEHPK3PXPAAAAB",
+        digits = "6",
+      )
+    )
+  }
+
+  @Test
+  fun otpGenerationUnusualSecrets() {
+    assertEquals(
+      "127764",
+      generateOtp(
+        counter = 1593367111963 / (1000 * 30),
+        secret = "JBSWY3DPEHPK3PXPAAAAAAAA",
+      )
+    )
+    assertEquals(
+      "047515",
+      generateOtp(
+        counter = 1593367171420 / (1000 * 30),
+        secret = "JBSWY3DPEHPK3PXPAAAAA",
+      )
+    )
+  }
+
+  @Test
+  fun otpGenerationUnpaddedSecrets() {
+    // Secret was generated with `echo 'string with some padding needed' | base32`
+    // We don't care for the resultant OTP's actual value, we just want both the padded and
+    // unpadded variant to generate the same one.
+    val unpaddedOtp =
+      generateOtp(
+        counter = 1593367171420 / (1000 * 30),
+        secret = "ON2HE2LOM4QHO2LUNAQHG33NMUQHAYLEMRUW4ZZANZSWKZDFMQFA",
+      )
+    val paddedOtp =
+      generateOtp(
+        counter = 1593367171420 / (1000 * 30),
+        secret = "ON2HE2LOM4QHO2LUNAQHG33NMUQHAYLEMRUW4ZZANZSWKZDFMQFA====",
+      )
+
+    assertNotNull(unpaddedOtp)
+    assertNotNull(paddedOtp)
+    assertEquals(unpaddedOtp, paddedOtp)
+  }
+
+  @Test
+  fun generateSteamTotp() {
+    val issuerOtp =
+      generateOtp(
+        counter = 48297900 / (1000 * 30),
+        secret = "STK7746GVMCHMNH5FBIAQXGPV3I7ZHRG",
+        issuer = "Steam",
+      )
+    val digitsOtp =
+      generateOtp(
+        counter = 48297900 / (1000 * 30),
+        secret = "STK7746GVMCHMNH5FBIAQXGPV3I7ZHRG",
+        digits = "s",
+      )
+    assertNotNull(issuerOtp)
+    assertNotNull(digitsOtp)
+    assertEquals("6M3CT", issuerOtp)
+    assertEquals("6M3CT", digitsOtp)
+  }
+}