diff --git a/core/data-test/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/test/FakeErrorMonitor.kt b/core/data-test/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/test/FakeErrorMonitor.kt
index cafa1d84a..2b6681aed 100644
--- a/core/data-test/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/test/FakeErrorMonitor.kt
+++ b/core/data-test/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/test/FakeErrorMonitor.kt
@@ -23,14 +23,41 @@ import kotlinx.coroutines.flow.flowOf
 import javax.inject.Inject
 
 class FakeErrorMonitor @Inject constructor() : ErrorMonitor {
-    override fun addErrorMessage(error: String): String? {
+
+    override var offlineMessage: String? = "offline"
+    override val isOffline: Flow<Boolean>
+        get() = flowOf(false)
+    override fun addShortErrorMessage(
+        error: String,
+        label: String?,
+        successAction: (() -> Unit)?,
+        failureAction: (() -> Unit)?,
+    ): String? {
         return "1"
     }
 
+    override fun addLongErrorMessage(
+        error: String,
+        label: String?,
+        successAction: (() -> Unit)?,
+        failureAction: (() -> Unit)?,
+    ): String? {
+        return "2"
+    }
+
+    override fun addIndefiniteErrorMessage(
+        error: String,
+        label: String?,
+        successAction: (() -> Unit)?,
+        failureAction: (() -> Unit)?,
+    ): String? {
+        return "3"
+    }
+
     override fun clearErrorMessage(id: String) {
         // Do nothing
     }
 
-    override val errorMessages: Flow<List<ErrorMessage?>>
-        get() = flowOf(emptyList())
+    override val errorMessage: Flow<ErrorMessage?>
+        get() = flowOf(null)
 }
diff --git a/core/data/src/test/kotlin/com/google/samples/apps/nowinandroid/core/data/util/SnackbarErrorMonitorTest.kt b/core/data/src/test/kotlin/com/google/samples/apps/nowinandroid/core/data/util/SnackbarErrorMonitorTest.kt
index 639b89092..1faac7f5b 100644
--- a/core/data/src/test/kotlin/com/google/samples/apps/nowinandroid/core/data/util/SnackbarErrorMonitorTest.kt
+++ b/core/data/src/test/kotlin/com/google/samples/apps/nowinandroid/core/data/util/SnackbarErrorMonitorTest.kt
@@ -15,11 +15,14 @@
  */
 
 import com.google.samples.apps.nowinandroid.core.data.util.ErrorMessage
+import com.google.samples.apps.nowinandroid.core.data.util.NetworkMonitor
 import com.google.samples.apps.nowinandroid.core.data.util.SnackbarErrorMonitor
+import com.google.samples.apps.nowinandroid.core.testing.util.TestNetworkMonitor
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
+import org.junit.Before
 import org.junit.Test
 import kotlin.test.assertEquals
 
@@ -29,14 +32,22 @@ import kotlin.test.assertEquals
 
 class SnackbarErrorMonitorTest {
 
+    lateinit var networkMonitor: NetworkMonitor
+
     // Subject under test.
-    private var state = SnackbarErrorMonitor()
+    private lateinit var state: SnackbarErrorMonitor
 
     private var message: ErrorMessage? = null
 
+    @Before
+    fun setup() {
+        networkMonitor = TestNetworkMonitor()
+        state = SnackbarErrorMonitor(networkMonitor)
+    }
+
     @Test
     fun whenErrorIsNotAdded_NullIsPresent() = runTest(UnconfinedTestDispatcher()) {
-        backgroundScope.launch { state.errorMessages.collect() }
+        backgroundScope.launch { state.errorMessage.collect() }
         assertEquals(
             null,
             message,
@@ -46,12 +57,12 @@ class SnackbarErrorMonitorTest {
     @Test
     fun whenErrorIsAdded_ErrorMessageIsPresent() = runTest(UnconfinedTestDispatcher()) {
         backgroundScope.launch {
-            state.errorMessages.collect {
-                message = it.firstOrNull()
+            state.errorMessage.collect {
+                message = it
             }
         }
 
-        val id = state.addErrorMessage("Test Error Message")
+        val id = state.addShortErrorMessage("Test Error Message")
 
         assertEquals(
             id,
@@ -62,12 +73,12 @@ class SnackbarErrorMonitorTest {
     @Test
     fun whenErrorsAreAdded_FirstErrorMessageIsPresent() =
         runTest(UnconfinedTestDispatcher()) {
-            val id1 = state.addErrorMessage("Test Error Message 1")
-            state.addErrorMessage("Test Error Message 2")
+            val id1 = state.addShortErrorMessage("Test Error Message 1")
+            state.addShortErrorMessage("Test Error Message 2")
 
             backgroundScope.launch {
-                state.errorMessages.collect {
-                    message = it.firstOrNull()
+                state.errorMessage.collect {
+                    message = it
                 }
             }
 
@@ -81,11 +92,11 @@ class SnackbarErrorMonitorTest {
     fun whenErrorIsCleared_ErrorMessageIsNotPresent() =
         runTest(UnconfinedTestDispatcher()) {
             backgroundScope.launch {
-                state.errorMessages.collect {
-                    message = it.firstOrNull()
+                state.errorMessage.collect {
+                    message = it
                 }
             }
-            val id = state.addErrorMessage("Test Error Message 1")
+            val id = state.addShortErrorMessage("Test Error Message 1")
             if (id != null) {
                 state.clearErrorMessage(id)
                 assertEquals(
@@ -99,12 +110,12 @@ class SnackbarErrorMonitorTest {
     fun whenErrorsAreCleared_NextErrorMessageIsPresent() =
         runTest(UnconfinedTestDispatcher()) {
             backgroundScope.launch {
-                state.errorMessages.collect {
-                    message = it.firstOrNull()
+                state.errorMessage.collect {
+                    message = it
                 }
             }
-            val id1 = state.addErrorMessage("Test Error Message 1")
-            val id2 = state.addErrorMessage("Test Error Message 2")
+            val id1 = state.addShortErrorMessage("Test Error Message 1")
+            val id2 = state.addShortErrorMessage("Test Error Message 2")
             if (id1 != null) {
                 state.clearErrorMessage(id1)
                 assertEquals(
diff --git a/core/testing/src/main/kotlin/com/google/samples/apps/nowinandroid/core/testing/util/TestErrorMonitor.kt b/core/testing/src/main/kotlin/com/google/samples/apps/nowinandroid/core/testing/util/TestErrorMonitor.kt
index b63bf2c02..c6f4ad3fa 100644
--- a/core/testing/src/main/kotlin/com/google/samples/apps/nowinandroid/core/testing/util/TestErrorMonitor.kt
+++ b/core/testing/src/main/kotlin/com/google/samples/apps/nowinandroid/core/testing/util/TestErrorMonitor.kt
@@ -22,14 +22,40 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flowOf
 
 class TestErrorMonitor : ErrorMonitor {
-    override fun addErrorMessage(error: String): String? {
+    override var offlineMessage: String? = "offline"
+    override val isOffline: Flow<Boolean>
+        get() = flowOf(false)
+    override fun addShortErrorMessage(
+        error: String,
+        label: String?,
+        successAction: (() -> Unit)?,
+        failureAction: (() -> Unit)?,
+    ): String? {
         return "1"
     }
 
+    override fun addLongErrorMessage(
+        error: String,
+        label: String?,
+        successAction: (() -> Unit)?,
+        failureAction: (() -> Unit)?,
+    ): String? {
+        return "2"
+    }
+
+    override fun addIndefiniteErrorMessage(
+        error: String,
+        label: String?,
+        successAction: (() -> Unit)?,
+        failureAction: (() -> Unit)?,
+    ): String? {
+        return "3"
+    }
+
     override fun clearErrorMessage(id: String) {
         // Do nothing
     }
 
-    override val errorMessages: Flow<List<ErrorMessage?>>
-        get() = flowOf(listOf(ErrorMessage("Error Message", "1")))
+    override val errorMessage: Flow<ErrorMessage?>
+        get() = flowOf(ErrorMessage("Error Message", "1"))
 }