diff --git a/.github/ci-config.properties b/.github/ci-config.properties
new file mode 100644
index 0000000..f9fddc5
--- /dev/null
+++ b/.github/ci-config.properties
@@ -0,0 +1,17 @@
+# Placeholder config used only by CI (see .github/workflows/ci.yml).
+# The real config-local.properties is gitignored and never committed.
+# These values are dummies so the Maven build's copy-config step has a file to copy.
+
+## Discord Settings
+discord.apiToken=ci-placeholder
+discord.guildID=0
+discord.channelID=0
+
+## Steam Settings
+steam.api=ci-placeholder
+
+## Leetify API
+leetify.apiToken=ci-placeholder
+
+## Carthage settings
+carthage.url=http://localhost/
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..7db739f
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,60 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Unit tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '21'
+          cache: maven
+
+      # config-local.properties is gitignored and holds secrets, so it is not in
+      # the repo. The build's copy-config step only needs the file to exist, so a
+      # placeholder is enough to compile and run the tests in CI.
+      - name: Generate placeholder config
+        run: cp .github/ci-config.properties src/main/resources/config-local.properties
+
+      - name: Run tests
+        run: mvn -B -ntp -P local test
+
+  build:
+    name: Build package
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '21'
+          cache: maven
+
+      - name: Generate placeholder config
+        run: cp .github/ci-config.properties src/main/resources/config-local.properties
+
+      - name: Build shaded jar
+        run: mvn -B -ntp -P local -DskipTests package
+
+      - name: Upload jar
+        uses: actions/upload-artifact@v4
+        with:
+          name: CounterStrikeBot-jar
+          path: target/CounterStrikeBot-*.jar
+          if-no-files-found: error
diff --git a/pom.xml b/pom.xml
index 64d5f5a..1f1c642 100644
--- a/pom.xml
+++ b/pom.xml
@@ -7,7 +7,7 @@
 
     <groupId>ch.yoinc</groupId>
     <artifactId>CounterStrikeBot</artifactId>
-    <version>3.6</version>
+    <version>3.7</version>
 
     <name>CounterStrikeBot</name>
     <url>https://github.com/yoinc-development/CounterStrikeBot</url>
@@ -67,7 +67,8 @@
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>5.12.0</version>
+            <version>5.23.0</version>
+            <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>net.kronos</groupId>
diff --git a/src/main/java/ch/yoinc/http/LeetifyConnection.java b/src/main/java/ch/yoinc/http/LeetifyConnection.java
index 4120103..ba84869 100644
--- a/src/main/java/ch/yoinc/http/LeetifyConnection.java
+++ b/src/main/java/ch/yoinc/http/LeetifyConnection.java
@@ -88,7 +88,9 @@ public List<LeetifyMatchResponse> getPlayerMatchHistory(String steam64ID, String
                 return gson.fromJson(response.body(), new TypeToken<List<LeetifyMatchResponse>>() {
                 }.getType());
             }
-            System.out.println("[CSBot - LeetifyConnection - " + LocalDateTime.now().format(DateTimeFormatter.ofPattern("dd.MM.yyyy - HH:mm:ss")) + "] getPlayerMatchHistory for " + parameter + " returned status " + response.statusCode() + ", body: " + response.body());
+            if(response.statusCode() != 404) {
+                System.out.println("[CSBot - LeetifyConnection - " + LocalDateTime.now().format(DateTimeFormatter.ofPattern("dd.MM.yyyy - HH:mm:ss")) + "] getPlayerMatchHistory for " + parameter + " returned status " + response.statusCode() + ", body: " + response.body());
+            }
         } catch (IOException | InterruptedException ex) {
             System.out.println("[CSBot - LeetifyConnection - " + LocalDateTime.now().format(DateTimeFormatter.ofPattern("dd.MM.yyyy - HH:mm:ss")) + "] IOException / InterruptedException thrown: " + ex.getMessage());
         }
diff --git a/src/main/java/ch/yoinc/tasks/LeetifyTask.java b/src/main/java/ch/yoinc/tasks/LeetifyTask.java
index 5980a26..51cb963 100644
--- a/src/main/java/ch/yoinc/tasks/LeetifyTask.java
+++ b/src/main/java/ch/yoinc/tasks/LeetifyTask.java
@@ -12,6 +12,7 @@
 import java.awt.*;
 import java.util.*;
 import java.util.List;
+import java.util.Locale;
 
 public class LeetifyTask implements ScheduledTask {
 
@@ -20,15 +21,13 @@ public class LeetifyTask implements ScheduledTask {
 
     @Override
     public void execute(JDA jda, Properties properties) {
-        dataService = new DataService(properties);
+        if (dataService == null) {
+            dataService = new DataService(properties);
+        }
+        if (leetifyConnection == null) {
+            leetifyConnection = new LeetifyConnection(properties);
+        }
         dataService.setBotID(jda.getSelfUser().getId());
-        leetifyConnection = new LeetifyConnection(properties);
-
-        DiscordService discordService = new DiscordService();
-
-        String DEFAULT_LEETIFY_URL = "https://leetify.com/app/match-details/%s/overview";
-        String DEFAULT_MAP_LOGO_URL = "https://raw.githubusercontent.com/MurkyYT/cs2-map-icons/main/images/%s.png";
-        String DEFAULT_MAP_URL = "https://raw.githubusercontent.com/MurkyYT/cs2-map-icons/main/images/thumbs/%s_1_png.png";
 
         List<InternalUser> internalUsers = dataService.getAllSteamUsers();
 
@@ -41,137 +40,83 @@ public void execute(JDA jda, Properties properties) {
 
         for (String matchID : newlyPlayedMatches.keySet()) {
             List<LeetifyMatchResponse> matches = newlyPlayedMatches.get(matchID);
+            EmbedBuilder matchEmbed = new EmbedBuilder();
+            LeetifyMatchResponse match = matches.getFirst();
+            boolean hasWon = match.stats.getFirst().rounds_won >= match.stats.getFirst().rounds_lost; //tie is a victory, change my mind
             if (matches.size() > 1) {
-                LeetifyMatchResponse match = matches.getFirst();
-                String title = "";
-                Color color = Color.BLUE;
-                String imageUrl = "";
-                String thumbnailUrl = "";
-                String footer = "";
-
                 List<String> playerNames = new ArrayList<>();
                 for (LeetifyMatchResponse playerMatch : matches) {
                     playerNames.add(playerMatch.stats.getFirst().name);
                 }
                 String players = String.join(", ", playerNames);
-                String description = "";
-
-                switch (match.data_source) {
-                    case "faceit":
-                        title = "New Faceit Match";
-                        color = Color.ORANGE;
-                        description = players + " played a new Faceit match together.";
-                        imageUrl = DEFAULT_MAP_URL.replace("%s", match.map_name);
-                        thumbnailUrl = DEFAULT_MAP_LOGO_URL.replace("%s", match.map_name);
-                        footer = "Finished at " + match.finished_at;
-                        break;
-                    case "wingman":
-                    case "matchmaking_wingman":
-                        title = "New Wingman Match";
-                        color = Color.GREEN;
-                        description = players + " played a new Wingman match together.";
-                        imageUrl = DEFAULT_MAP_URL.replace("%s", match.map_name);
-                        thumbnailUrl = DEFAULT_MAP_LOGO_URL.replace("%s", match.map_name);
-                        footer = "Finished at " + match.finished_at;
-                        break;
-                    case "premier":
-                        title = "New Premier Match";
-                        color = Color.YELLOW;
-                        description = players + " played a new Premier match together.";
-                        imageUrl = DEFAULT_MAP_URL.replace("%s", match.map_name);
-                        thumbnailUrl = DEFAULT_MAP_LOGO_URL.replace("%s", match.map_name);
-                        footer = "Finished at " + match.finished_at;
-                        break;
-                    case "matchmaking":
-                        title = "New Competitive Match";
-                        color = Color.RED;
-                        description = players + " played a new Competitive match together.";
-                        imageUrl = DEFAULT_MAP_URL.replace("%s", match.map_name);
-                        thumbnailUrl = DEFAULT_MAP_LOGO_URL.replace("%s", match.map_name);
-                        footer = "Finished at " + match.finished_at;
-                        break;
-                }
 
-                EmbedBuilder updateMessage = discordService.createEmbedBuilder(title, description, imageUrl, footer);
-                updateMessage
-                        .setTitle(title, DEFAULT_LEETIFY_URL.replace("%s", matchID))
-                        .setColor(color)
-                        .setThumbnail(thumbnailUrl);
+                matchEmbed = switch (match.data_source) {
+                    case "faceit" -> returnFilledEmbed("New Faceit Match",
+                            Color.ORANGE, players + " played a Faceit match together and " + ((hasWon) ? "**won**." :  "**lost**."),
+                            match.map_name, matchID, "Finished at " + match.finished_at);
+                    case "matchmaking_wingman" -> returnFilledEmbed("New Wingman Match",
+                            Color.GREEN, players + " played a Wingman match together and " + ((hasWon) ? "**won**." :  "**lost**."),
+                            match.map_name, matchID, "Finished at " + match.finished_at);
+                    case "matchmaking" -> returnFilledEmbed("New Competitive Match",
+                            Color.YELLOW, players + " played a Competitive match together and " + ((hasWon) ? "**won**." :  "**lost**."),
+                            match.map_name, matchID, "Finished at " + match.finished_at);
+                    default -> matchEmbed;
+                };
 
                 for (LeetifyMatchResponse playerMatch : matches) {
                     LeetifyPlayerStatsResponse stats = playerMatch.stats.getFirst();
-                    updateMessage.addField(
+                    matchEmbed.addField(
                             stats.name,
                             "Kills: " + stats.total_kills +
                                     "\nDeaths: " + stats.total_deaths +
                                     "\nADR: " + stats.dpr +
-                                    "\nRating: " + stats.leetify_rating +
-                                    "\nCT Rating: " + stats.ct_leetify_rating +
-                                    "\nT Rating: " + stats.t_leetify_rating,
+                                    "\nRating: " + formatRating(stats.leetify_rating) +
+                                    "\nCT Rating: " + formatRating(stats.ct_leetify_rating) +
+                                    "\nT Rating: " + formatRating(stats.t_leetify_rating),
                             true
                     );
                 }
-                Objects.requireNonNull(jda.getTextChannelById(properties.getProperty("discord.channelID"))).sendMessageEmbeds(updateMessage.build()).queue();
             } else {
-                LeetifyMatchResponse match = matches.getFirst();
-                String title = "";
-                Color color = Color.BLUE;
-                String description = "";
-                String imageUrl = "";
-                String thumbnailUrl = "";
-                String footer = "";
-
-                switch (match.data_source) {
-                    case "faceit":
-                        title = "New Faceit Match";
-                        color = Color.ORANGE;
-                        description = match.stats.getFirst().name + " played a new Faceit match.";
-                        imageUrl = DEFAULT_MAP_URL.replace("%s", match.map_name);
-                        thumbnailUrl = DEFAULT_MAP_LOGO_URL.replace("%s", match.map_name);
-                        footer = "Finished at " + match.finished_at;
-                        break;
-                    case "wingman":
-                    case "matchmaking_wingman":
-                        title = "New Wingman Match";
-                        color = Color.GREEN;
-                        description = match.stats.getFirst().name + " played a new Wingman match.";
-                        imageUrl = DEFAULT_MAP_URL.replace("%s", match.map_name);
-                        thumbnailUrl = DEFAULT_MAP_LOGO_URL.replace("%s", match.map_name);
-                        footer = "Finished at " + match.finished_at;
-                        break;
-                    case "premier":
-                        title = "New Premier Match";
-                        color = Color.YELLOW;
-                        description = match.stats.getFirst().name + " played a new Premier match.";
-                        imageUrl = DEFAULT_MAP_URL.replace("%s", match.map_name);
-                        thumbnailUrl = DEFAULT_MAP_LOGO_URL.replace("%s", match.map_name);
-                        footer = "Finished at " + match.finished_at;
-                        break;
-                    case "matchmaking":
-                        title = "New Competitive Match";
-                        color = Color.RED;
-                        description = match.stats.getFirst().name + " played a new Competitive match.";
-                        imageUrl = DEFAULT_MAP_URL.replace("%s", match.map_name);
-                        thumbnailUrl = DEFAULT_MAP_LOGO_URL.replace("%s", match.map_name);
-                        footer = "Finished at " + match.finished_at;
-                        break;
-                }
-                EmbedBuilder updateMessage = discordService.createEmbedBuilder(title, description, imageUrl, footer);
-                updateMessage
-                        .setTitle(title, DEFAULT_LEETIFY_URL.replace("%s", matchID))
-                        .setColor(color)
-                        .setThumbnail(thumbnailUrl)
+                matchEmbed = switch (match.data_source) {
+                    case "faceit" -> returnFilledEmbed("New Faceit Match", Color.ORANGE,
+                            match.stats.getFirst().name + " played a Faceit match and " + ((hasWon) ? "**won**." :  "**lost**."),
+                            match.map_name, matchID, "Finished at " + match.finished_at);
+                    case "matchmaking_wingman" -> returnFilledEmbed("New Wingman Match", Color.GREEN,
+                            match.stats.getFirst().name + " played a Wingman match and " + ((hasWon) ? "**won**." :  "**lost**."),
+                            match.map_name, matchID, "Finished at " + match.finished_at);
+                    case "matchmaking" -> returnFilledEmbed("New Competitive Match", Color.YELLOW,
+                            match.stats.getFirst().name + " played a Competitive match and " + ((hasWon) ? "**won**." :  "**lost**."),
+                            match.map_name, matchID, "Finished at " + match.finished_at);
+                    default -> matchEmbed;
+                };
+                matchEmbed
                         .addField("Kills", Integer.toString(match.stats.getFirst().total_kills), true)
                         .addField("Deaths", Integer.toString(match.stats.getFirst().total_deaths), true)
                         .addField("ADR", Double.toString(match.stats.getFirst().dpr), true)
-                        .addField("Rating", Double.toString(match.stats.getFirst().leetify_rating), true)
-                        .addField("CT Rating", Double.toString(match.stats.getFirst().ct_leetify_rating), true)
-                        .addField("T Rating", Double.toString(match.stats.getFirst().t_leetify_rating), true);
-                Objects.requireNonNull(jda.getTextChannelById(properties.getProperty("discord.channelID"))).sendMessageEmbeds(updateMessage.build()).queue();
+                        .addField("Rating", formatRating(match.stats.getFirst().leetify_rating), true)
+                        .addField("CT Rating", formatRating(match.stats.getFirst().ct_leetify_rating), true)
+                        .addField("T Rating", formatRating(match.stats.getFirst().t_leetify_rating), true);
             }
+            Objects.requireNonNull(jda.getTextChannelById(properties.getProperty("discord.channelID"))).sendMessageEmbeds(matchEmbed.build()).queue();
         }
     }
 
+    private EmbedBuilder returnFilledEmbed(String title, Color color, String description, String map_name, String matchID, String footer) {
+        DiscordService discordService = new DiscordService();
+
+        String DEFAULT_LEETIFY_URL = "https://leetify.com/app/match-details/%s/overview";
+        String DEFAULT_MAP_LOGO_URL = "https://raw.githubusercontent.com/MurkyYT/cs2-map-icons/main/images/%s.png";
+        String DEFAULT_MAP_URL = "https://raw.githubusercontent.com/MurkyYT/cs2-map-icons/main/images/thumbs/%s_1_png.png";
+
+        EmbedBuilder returnEmbed = discordService.createEmbedBuilder(title, description, DEFAULT_MAP_URL.replace("%s", map_name), footer);
+        returnEmbed
+                .setTitle(title, DEFAULT_LEETIFY_URL.replace("%s", matchID))
+                .setColor(color)
+                .setThumbnail(DEFAULT_MAP_LOGO_URL.replace("%s", map_name));
+
+        return returnEmbed;
+    }
+
     private HashMap<String, List<LeetifyMatchResponse>> setNewlyPlayedMatches(List<InternalUser> steamInternalUsers) {
         HashMap<String, List<LeetifyMatchResponse>> results = new HashMap<>();
 
@@ -204,4 +149,11 @@ private HashMap<String, List<LeetifyMatchResponse>> setNewlyPlayedMatches(List<I
     public String getTaskName() {
         return "LeetifyTask";
     }
+
+    private static String formatRating(Double rating) {
+        if (rating == null) {
+            return "n/a";
+        }
+        return String.format(Locale.US, "%.2f", rating * 100.0);
+    }
 }
diff --git a/src/main/java/ch/yoinc/tasks/TaskScheduler.java b/src/main/java/ch/yoinc/tasks/TaskScheduler.java
index 3ab5cb9..539e277 100644
--- a/src/main/java/ch/yoinc/tasks/TaskScheduler.java
+++ b/src/main/java/ch/yoinc/tasks/TaskScheduler.java
@@ -67,6 +67,6 @@ public void run() {
             }
         };
 
-        timer.schedule(timerTask, initialDelay, interval);
+        timer.scheduleAtFixedRate(timerTask, initialDelay, interval);
     }
 }
\ No newline at end of file
diff --git a/src/test/java/ch/yoinc/tasks/LeetifyTaskTest.java b/src/test/java/ch/yoinc/tasks/LeetifyTaskTest.java
new file mode 100644
index 0000000..c2fdf80
--- /dev/null
+++ b/src/test/java/ch/yoinc/tasks/LeetifyTaskTest.java
@@ -0,0 +1,249 @@
+package ch.yoinc.tasks;
+
+import ch.yoinc.http.LeetifyConnection;
+import ch.yoinc.model.internal.InternalUser;
+import ch.yoinc.model.leetify.LeetifyMatchResponse;
+import ch.yoinc.model.leetify.LeetifyPlayerStatsResponse;
+import ch.yoinc.services.DataService;
+import net.dv8tion.jda.api.EmbedBuilder;
+import net.dv8tion.jda.api.entities.MessageEmbed;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+
+import java.awt.Color;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.time.Instant;
+import java.util.HashMap;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.ArgumentMatchers.isNull;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+class LeetifyTaskTest {
+
+    private LeetifyTask task;
+
+    @BeforeEach
+    void setUp() {
+        task = new LeetifyTask();
+    }
+
+    // ---------------------------------------------------------------------
+    // returnFilledEmbed
+    // ---------------------------------------------------------------------
+
+    @Test
+    void returnFilledEmbed_setsTitleAndMatchUrl() throws Exception {
+        MessageEmbed embed = invokeReturnFilledEmbed("New Faceit Match", Color.ORANGE,
+                "players played a match", "de_dust2", "match-123", "Finished at 2026-01-01");
+
+        assertEquals("New Faceit Match", embed.getTitle());
+        assertEquals("https://leetify.com/app/match-details/match-123/overview", embed.getUrl());
+    }
+
+    @Test
+    void returnFilledEmbed_setsColorDescriptionAndFooter() throws Exception {
+        MessageEmbed embed = invokeReturnFilledEmbed("New Competitive Match", Color.RED,
+                "some description", "de_mirage", "match-456", "Finished at 2026-01-02");
+
+        assertEquals(Color.RED, embed.getColor());
+        assertEquals("some description", embed.getDescription());
+        assertEquals("Finished at 2026-01-02", embed.getFooter().getText());
+    }
+
+    @Test
+    void returnFilledEmbed_buildsMapImageAndThumbnailUrlsFromMapName() throws Exception {
+        MessageEmbed embed = invokeReturnFilledEmbed("New Wingman Match", Color.GREEN,
+                "desc", "de_inferno", "match-789", "footer");
+
+        assertEquals("https://raw.githubusercontent.com/MurkyYT/cs2-map-icons/main/images/thumbs/de_inferno_1_png.png",
+                embed.getImage().getUrl());
+        assertEquals("https://raw.githubusercontent.com/MurkyYT/cs2-map-icons/main/images/de_inferno.png",
+                embed.getThumbnail().getUrl());
+    }
+
+    @Test
+    void returnFilledEmbed_appliesYoincBranding() throws Exception {
+        MessageEmbed embed = invokeReturnFilledEmbed("New Premier Match", Color.YELLOW,
+                "desc", "de_ancient", "match-321", "footer");
+
+        assertNotNull(embed.getAuthor());
+        assertEquals("Powered by YOINC.", embed.getAuthor().getName());
+    }
+
+    // ---------------------------------------------------------------------
+    // formatRating
+    // ---------------------------------------------------------------------
+
+    @Test
+    void formatRating_scalesToPercentageAndRoundsToTwoDecimals() throws Exception {
+        assertEquals("1.23", invokeFormatRating(0.0123));
+        assertEquals("5.32", invokeFormatRating(0.0532));
+        assertEquals("-0.71", invokeFormatRating(-0.0071));
+    }
+
+    @Test
+    void formatRating_returnsPlaceholder_whenRatingIsMissing() throws Exception {
+        assertEquals("n/a", invokeFormatRating(null));
+    }
+
+    // ---------------------------------------------------------------------
+    // setNewlyPlayedMatches
+    // ---------------------------------------------------------------------
+
+    @Test
+    @Timeout(value = 5, unit = TimeUnit.SECONDS)
+    void setNewlyPlayedMatches_returnsEmptyMap_whenUserHasNoMatchHistory() throws Exception {
+        DataService dataService = mock(DataService.class);
+        LeetifyConnection leetifyConnection = mock(LeetifyConnection.class);
+        when(leetifyConnection.getPlayerMatchHistory(eq("STEAM1"), isNull())).thenReturn(null);
+        injectDependencies(dataService, leetifyConnection);
+
+        // the method sleeps 10s (real) after every user; pre-interrupting this thread makes
+        // that Thread.sleep() throw immediately instead of actually waiting
+        Thread.currentThread().interrupt();
+
+        HashMap<String, List<LeetifyMatchResponse>> results = invokeSetNewlyPlayedMatches(List.of(user(1, "STEAM1")));
+
+        assertTrue(results.isEmpty());
+        verify(dataService, never()).insertAndGetNewMatches(any(), any());
+        assertTrue(Thread.interrupted(), "interrupt flag should have been restored by the method");
+    }
+
+    @Test
+    @Timeout(value = 5, unit = TimeUnit.SECONDS)
+    void setNewlyPlayedMatches_onlyIncludesMatchesReturnedAsNew() throws Exception {
+        DataService dataService = mock(DataService.class);
+        LeetifyConnection leetifyConnection = mock(LeetifyConnection.class);
+
+        LeetifyMatchResponse oldMatch = match("old-match", "Alice");
+        LeetifyMatchResponse newMatch = match("new-match", "Alice");
+        List<LeetifyMatchResponse> history = List.of(oldMatch, newMatch);
+        when(leetifyConnection.getPlayerMatchHistory(eq("STEAM1"), isNull())).thenReturn(history);
+        when(dataService.insertAndGetNewMatches(history, 1)).thenReturn(List.of("new-match"));
+        injectDependencies(dataService, leetifyConnection);
+
+        Thread.currentThread().interrupt();
+
+        HashMap<String, List<LeetifyMatchResponse>> results = invokeSetNewlyPlayedMatches(List.of(user(1, "STEAM1")));
+
+        assertEquals(1, results.size());
+        assertFalse(results.containsKey("old-match"));
+        assertEquals(List.of(newMatch), results.get("new-match"));
+        Thread.interrupted();
+    }
+
+    @Test
+    @Timeout(value = 12, unit = TimeUnit.SECONDS)
+    void setNewlyPlayedMatches_groupsMatchesFromDifferentUsersUnderSameMatchId() throws Exception {
+        DataService dataService = mock(DataService.class);
+        LeetifyConnection leetifyConnection = mock(LeetifyConnection.class);
+
+        LeetifyMatchResponse aliceMatch = match("shared-match", "Alice");
+        LeetifyMatchResponse bobMatch = match("shared-match", "Bob");
+        List<LeetifyMatchResponse> aliceHistory = List.of(aliceMatch);
+        List<LeetifyMatchResponse> bobHistory = List.of(bobMatch);
+
+        when(leetifyConnection.getPlayerMatchHistory(eq("STEAM1"), isNull())).thenReturn(aliceHistory);
+        when(leetifyConnection.getPlayerMatchHistory(eq("STEAM2"), isNull())).thenReturn(bobHistory);
+        when(dataService.insertAndGetNewMatches(aliceHistory, 1)).thenReturn(List.of("shared-match"));
+        when(dataService.insertAndGetNewMatches(bobHistory, 2)).thenReturn(List.of("shared-match"));
+        injectDependencies(dataService, leetifyConnection);
+
+        // the production loop sleeps 10s (real) between users, so the first sleep has to be
+        // waited out for the second user to be processed at all; once it's back we interrupt
+        // the worker to skip its trailing sleep instead of waiting a second 10s
+        AtomicReference<HashMap<String, List<LeetifyMatchResponse>>> resultRef = new AtomicReference<>();
+        Thread worker = new Thread(() -> {
+            try {
+                resultRef.set(invokeSetNewlyPlayedMatches(List.of(user(1, "STEAM1"), user(2, "STEAM2"))));
+            } catch (Exception e) {
+                throw new RuntimeException(e);
+            }
+        });
+        worker.start();
+        worker.join(10_500);
+        if (worker.isAlive()) {
+            worker.interrupt();
+            worker.join(2_000);
+        }
+
+        HashMap<String, List<LeetifyMatchResponse>> results = resultRef.get();
+        assertNotNull(results, "worker did not finish in time");
+        assertEquals(1, results.size());
+        assertEquals(List.of(aliceMatch, bobMatch), results.get("shared-match"));
+    }
+
+    // ---------------------------------------------------------------------
+    // helpers
+    // ---------------------------------------------------------------------
+
+    private MessageEmbed invokeReturnFilledEmbed(String title, Color color, String description,
+                                                 String mapName, String matchId, String footer) throws Exception {
+        Method method = LeetifyTask.class.getDeclaredMethod("returnFilledEmbed",
+                String.class, Color.class, String.class, String.class, String.class, String.class);
+        method.setAccessible(true);
+        EmbedBuilder builder = (EmbedBuilder) method.invoke(task, title, color, description, mapName, matchId, footer);
+        return builder.build();
+    }
+
+    private String invokeFormatRating(Double rating) throws Exception {
+        Method method = LeetifyTask.class.getDeclaredMethod("formatRating", Double.class);
+        method.setAccessible(true);
+        return (String) method.invoke(null, rating);
+    }
+
+    @SuppressWarnings("unchecked")
+    private HashMap<String, List<LeetifyMatchResponse>> invokeSetNewlyPlayedMatches(List<InternalUser> users) {
+        try {
+            Method method = LeetifyTask.class.getDeclaredMethod("setNewlyPlayedMatches", List.class);
+            method.setAccessible(true);
+            return (HashMap<String, List<LeetifyMatchResponse>>) method.invoke(task, users);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private void injectDependencies(DataService dataService, LeetifyConnection leetifyConnection) throws Exception {
+        setPrivateField("dataService", dataService);
+        setPrivateField("leetifyConnection", leetifyConnection);
+    }
+
+    private void setPrivateField(String name, Object value) throws Exception {
+        Field field = LeetifyTask.class.getDeclaredField(name);
+        field.setAccessible(true);
+        field.set(task, value);
+    }
+
+    private static InternalUser user(int id, String steamId) {
+        InternalUser user = new InternalUser();
+        user.userID = id;
+        user.steamID = steamId;
+        return user;
+    }
+
+    private static LeetifyMatchResponse match(String matchId, String playerName) {
+        LeetifyMatchResponse match = new LeetifyMatchResponse();
+        match.id = matchId;
+        match.data_source = "matchmaking";
+        match.map_name = "de_dust2";
+        match.finished_at = Instant.now();
+        LeetifyPlayerStatsResponse stats = new LeetifyPlayerStatsResponse();
+        stats.name = playerName;
+        match.stats = List.of(stats);
+        return match;
+    }
+}