diff --git a/.ci/Arch/Dockerfile b/.ci/Arch/Dockerfile
index b08e568f3..4dc2f5e90 100644
--- a/.ci/Arch/Dockerfile
+++ b/.ci/Arch/Dockerfile
@@ -1,9 +1,9 @@
-from archlinux:latest
+FROM archlinux:latest
 
 RUN pacman --sync --refresh --sysupgrade --needed --noconfirm \
-        base-devel \
         ccache \
         cmake \
+        gcc \
         git \
         gtest \
         mariadb-libs \
diff --git a/.ci/Debian12/Dockerfile b/.ci/Debian12/Dockerfile
index 4da910dc0..03f33b38e 100644
--- a/.ci/Debian12/Dockerfile
+++ b/.ci/Debian12/Dockerfile
@@ -1,16 +1,17 @@
-FROM debian:12
+FROM debian:12-slim
 
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-        build-essential \
         ca-certificates \
         ccache \
         cmake \
+        dpkg-dev \
         file \
         g++ \
         git \
         libcurl4-openssl-dev \
         libgl-dev \
+        libgtest-dev \
         liblzma-dev \
         libmariadb-dev-compat \
         libprotobuf-dev \
diff --git a/.ci/Debian13/Dockerfile b/.ci/Debian13/Dockerfile
index 94f711398..8ee8cccff 100644
--- a/.ci/Debian13/Dockerfile
+++ b/.ci/Debian13/Dockerfile
@@ -1,16 +1,17 @@
-FROM debian:13
+FROM debian:13-slim
 
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-        build-essential \
         ca-certificates \
         ccache \
         cmake \
+        dpkg-dev \
         file \
         g++ \
         git \
         libcurl4-openssl-dev \
         libgl-dev \
+        libgtest-dev \
         liblzma-dev \
         libmariadb-dev-compat \
         libprotobuf-dev \
diff --git a/.ci/Fedora44/Dockerfile b/.ci/Fedora44/Dockerfile
index 15204fa1a..d02649b4d 100644
--- a/.ci/Fedora44/Dockerfile
+++ b/.ci/Fedora44/Dockerfile
@@ -1,11 +1,12 @@
 FROM fedora:44
 
-RUN dnf install -y \
+RUN dnf install -y --nodocs \
         ca-certificates \
         ccache \
         cmake \
         gcc-c++ \
         git \
+        gtest-devel \
         libcurl-devel \
         mariadb-devel \
         ninja-build \
diff --git a/.ci/Fedora45/Dockerfile b/.ci/Fedora45/Dockerfile
index a7c49b249..5527aac87 100644
--- a/.ci/Fedora45/Dockerfile
+++ b/.ci/Fedora45/Dockerfile
@@ -1,11 +1,12 @@
 FROM fedora:45
 
-RUN dnf install -y \
+RUN dnf install -y --nodocs \
         ca-certificates \
         ccache \
         cmake \
         gcc-c++ \
         git \
+        gtest-devel \
         libcurl-devel \
         mariadb-devel \
         ninja-build \
diff --git a/.ci/Servatrice_Debian12/Dockerfile b/.ci/Servatrice_Debian12/Dockerfile
index f1a16843a..8c166a85b 100644
--- a/.ci/Servatrice_Debian12/Dockerfile
+++ b/.ci/Servatrice_Debian12/Dockerfile
@@ -1,10 +1,10 @@
-FROM debian:12
+FROM debian:12-slim
 
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-        build-essential \
         ccache \
         cmake \
+        dpkg-dev \
         file \
         g++ \
         git \
diff --git a/.ci/Ubuntu24.04/Dockerfile b/.ci/Ubuntu24.04/Dockerfile
index 43497dd3b..47f927f41 100644
--- a/.ci/Ubuntu24.04/Dockerfile
+++ b/.ci/Ubuntu24.04/Dockerfile
@@ -2,15 +2,16 @@ FROM ubuntu:24.04
 
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-        build-essential \
         ca-certificates \
         ccache \
         cmake \
+        dpkg-dev \
         file \
         g++ \
         git \
         libcurl4-openssl-dev \
         libgl-dev \
+        libgtest-dev \
         liblzma-dev \
         libmariadb-dev-compat \
         libprotobuf-dev \
diff --git a/.ci/Ubuntu26.04/Dockerfile b/.ci/Ubuntu26.04/Dockerfile
index 4dc861ae9..f50a3cec2 100644
--- a/.ci/Ubuntu26.04/Dockerfile
+++ b/.ci/Ubuntu26.04/Dockerfile
@@ -2,16 +2,17 @@ FROM ubuntu:26.04
 
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-        build-essential \
         ca-certificates \
         ccache \
         cmake \
+        dpkg-dev \
         file \
         g++ \
         gcovr \
         git \
         libcurl4-openssl-dev \
         libgl-dev \
+        libgtest-dev \
         liblzma-dev \
         libmariadb-dev-compat \
         libprotobuf-dev \
diff --git a/tests/latency_tracker_test.cpp b/tests/latency_tracker_test.cpp
index a77051799..a8ecf9e8d 100644
--- a/tests/latency_tracker_test.cpp
+++ b/tests/latency_tracker_test.cpp
@@ -3,8 +3,12 @@
 #include <gtest/gtest.h>
 #include <initializer_list>
 #include <libcockatrice/network/client/abstract/latency_tracker.h>
+#include <libcockatrice/rng/rng_abstract.h>
 #include <string>
 
+// Referenced by other translation units in the server_remote library.
+RNG_Abstract *rng = nullptr;
+
 TEST(LatencyTrackerTest, EmptyTrackerYieldsZeroedStats)
 {
     LatencyTracker tracker;
diff --git a/tests/loader_local_matching_test.cpp b/tests/loader_local_matching_test.cpp
index 7632e60d4..ef6018790 100644
--- a/tests/loader_local_matching_test.cpp
+++ b/tests/loader_local_matching_test.cpp
@@ -23,10 +23,14 @@
 #include <libcockatrice/card/printing/exact_card.h>
 #include <libcockatrice/card/set/card_set.h>
 #include <libcockatrice/interfaces/noop_card_set_priority_controller.h>
+#include <libcockatrice/rng/rng_abstract.h>
 #include <libcockatrice/settings/paths_settings.h>
 #include <qnamespace.h>
 #include <string>
 
+// Referenced by other translation units in the server_remote library.
+RNG_Abstract *rng = nullptr;
+
 namespace
 {
 
diff --git a/tests/server_counter_test.cpp b/tests/server_counter_test.cpp
index 492aecf66..f894abdbf 100644
--- a/tests/server_counter_test.cpp
+++ b/tests/server_counter_test.cpp
@@ -8,9 +8,13 @@
 #include <QString>
 #include <gtest/gtest.h>
 #include <libcockatrice/network/server/remote/game/server_counter.h>
+#include <libcockatrice/rng/rng_abstract.h>
 #include <limits>
 #include <string>
 
+// Referenced by other translation units in the server_remote library.
+RNG_Abstract *rng = nullptr;
+
 TEST(ServerCounter, IncrementDoesNotOverflow)
 {
     Server_Counter c(1, "test", color(), 10, std::numeric_limits<int>::max());