diff --git a/backend/src/test/kotlin/com/condado/newsletter/service/EmailReaderServiceTest.kt b/backend/src/test/kotlin/com/condado/newsletter/service/EmailReaderServiceTest.kt
new file mode 100644
index 0000000..de9daff
--- /dev/null
+++ b/backend/src/test/kotlin/com/condado/newsletter/service/EmailReaderServiceTest.kt
@@ -0,0 +1,113 @@
+package com.condado.newsletter.service
+
+import io.mockk.every
+import io.mockk.mockk
+import jakarta.mail.Folder
+import jakarta.mail.Message
+import jakarta.mail.Session
+import jakarta.mail.Store
+import jakarta.mail.internet.InternetAddress
+import jakarta.mail.internet.MimeMessage
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import java.time.LocalDateTime
+import java.util.Date
+
+class EmailReaderServiceTest {
+
+    private val mockStore: Store = mockk(relaxed = true)
+    private val service = EmailReaderService(storeFactory = { mockStore })
+
+    @Test
+    fun should_returnEmailsSortedChronologically_when_multipleEmailsFetched() {
+        val folder: Folder = mockk(relaxed = true)
+        val session: Session = mockk()
+
+        val newer = buildMimeMessage(session, "Newer email", "bob@x.com", Date())
+        val older = buildMimeMessage(session, "Older email", "alice@x.com", Date(System.currentTimeMillis() - 100_000))
+
+        every { mockStore.getFolder(any<String>()) } returns folder
+        every { folder.messageCount } returns 2
+        every { folder.getMessages() } returns arrayOf(newer, older)
+
+        val result = service.readEmails("INBOX", contextWindowDays = 10)
+
+        assertThat(result).hasSize(2)
+        assertThat(result[0].subject).isEqualTo("Older email")
+        assertThat(result[1].subject).isEqualTo("Newer email")
+    }
+
+    @Test
+    fun should_returnEmptyList_when_imapConnectionFails() {
+        every { mockStore.getFolder(any<String>()) } throws RuntimeException("Connection refused")
+
+        val result = service.readEmails("INBOX", contextWindowDays = 3)
+
+        assertThat(result).isEmpty()
+    }
+
+    @Test
+    fun should_filterEmailsOlderThanContextWindow_when_windowIs3Days() {
+        val folder: Folder = mockk(relaxed = true)
+        val session: Session = mockk()
+
+        val recentDate = Date()
+        val oldDate = Date(System.currentTimeMillis() - 10L * 24 * 60 * 60 * 1000)
+
+        val recent = buildMimeMessage(session, "Recent", "a@x.com", recentDate)
+        val old = buildMimeMessage(session, "Old", "b@x.com", oldDate)
+
+        every { mockStore.getFolder(any<String>()) } returns folder
+        every { folder.messageCount } returns 2
+        every { folder.getMessages() } returns arrayOf(recent, old)
+
+        val result = service.readEmails("INBOX", contextWindowDays = 3)
+
+        assertThat(result).hasSize(1)
+        assertThat(result[0].subject).isEqualTo("Recent")
+    }
+
+    @Test
+    fun should_stripHtml_when_emailBodyContainsHtmlTags() {
+        val folder: Folder = mockk(relaxed = true)
+        val session: Session = mockk()
+
+        val msg = buildMimeMessage(
+            session,
+            subject = "HTML email",
+            from = "dev@x.com",
+            date = Date(),
+            body = "<p>Hello <b>world</b></p>"
+        )
+
+        every { mockStore.getFolder(any<String>()) } returns folder
+        every { folder.messageCount } returns 1
+        every { folder.getMessages() } returns arrayOf(msg)
+
+        val result = service.readEmails("INBOX", contextWindowDays = 10)
+
+        assertThat(result).hasSize(1)
+        assertThat(result[0].body).doesNotContain("<p>", "<b>", "</b>", "</p>")
+        assertThat(result[0].body).contains("Hello")
+        assertThat(result[0].body).contains("world")
+    }
+
+    // ── helper ──────────────────────────────────────────────────────────────
+
+    private fun buildMimeMessage(
+        session: Session,
+        subject: String,
+        from: String,
+        date: Date,
+        body: String = "Plain text body"
+    ): MimeMessage {
+        val msg: MimeMessage = mockk(relaxed = true)
+        every { msg.subject } returns subject
+        every { msg.from } returns arrayOf(InternetAddress(from))
+        every { msg.sentDate } returns date
+        every { msg.receivedDate } returns date
+        every { msg.contentType } returns "text/plain"
+        every { msg.content } returns body
+        return msg
+    }
+}