diff --git a/sh/tests/Dockerfile b/sh/tests/Dockerfile
index 63f5fd32..dfbc03ec 100644
--- a/sh/tests/Dockerfile
+++ b/sh/tests/Dockerfile
@@ -2,5 +2,7 @@ FROM debian:stable-slim
 
 RUN apt-get update
 RUN apt-get -y install jq curl git
+COPY --from=mkcert-ca . /usr/local/share/ca-certificates
+RUN update-ca-certificates
 COPY . /app
 ENTRYPOINT ["/bin/bash", "/app/entrypoint.sh"]
diff --git a/sh/tests/solutions/myfamily.sh b/sh/tests/solutions/myfamily.sh
index c2ed75ff..a1549631 100755
--- a/sh/tests/solutions/myfamily.sh
+++ b/sh/tests/solutions/myfamily.sh
@@ -5,9 +5,5 @@ set -euo pipefail
 IFS='
 '
 
-f=""
-# --insecure flag to make it work with dev environment (self-signed certificate)
-test "$DOMAIN" = "localhost" && f="--insecure"
-
-curl $f --compressed --silent --show-error --max-time 10 https://$DOMAIN/assets/superhero/all.json |
+curl --compressed --silent --show-error --max-time 10 https://$DOMAIN/assets/superhero/all.json |
     jq ".[] | select(.id == $HERO_ID)" | grep relatives | cut -d'"' -f4
diff --git a/sh/tests/solutions/who-are-you.sh b/sh/tests/solutions/who-are-you.sh
index 27681479..6eb82adf 100755
--- a/sh/tests/solutions/who-are-you.sh
+++ b/sh/tests/solutions/who-are-you.sh
@@ -5,9 +5,5 @@ set -euo pipefail
 IFS='
 '
 
-f=""
-# --insecure flag to make it work with dev environment (self-signed certificate)
-test "$DOMAIN" = "localhost" && f="--insecure"
-
-curl $f --compressed --silent --show-error --max-time 10 https://$DOMAIN/assets/superhero/all.json |
+curl --compressed --silent --show-error --max-time 10 "https://$DOMAIN/assets/superhero/all.json" |
     jq '.[] | select(.id == 70) | .name'