diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8252b041b8f0e9082af5a5576dfd39a5e338a503..5ac789faccae19f98ba59dd94f7806b665358aa3 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -23,10 +23,10 @@ hlint:
     nix run .#hlint -- src/ test/
 
 # Use cabal to build the library and test suite and then run the test suite.
-cabal-build-and-test:
+"cabal-build-and-test-8.6.5":
   script:
     - |
-      nix run .#cabal-test
+      nix run .#cabal-test-865
 
 # Use nix to build the library and test suite and run the test suite.
 nix-build-and-test:
diff --git a/flake.nix b/flake.nix
index ced2464ab54332a86ca8ea1deec37bdb93dea1a2..68d34083243f121e673b25b1239951a6487ae8ee 100644
--- a/flake.nix
+++ b/flake.nix
@@ -28,20 +28,22 @@
         compilerVersion = ghcVersion;
         packageName = "tahoe-chk";
       };
-    in {
-      checks = hslib.checks {};
-      devShells = hslib.devShells {};
-      packages = hslib.packages {};
-      apps.hlint = hslib.apps.hlint {};
 
-      # Using the working directory of `nix run`, do a build with cabal and
-      # then run the test suite.
-      apps.cabal-test = {
+      # string -> flake app
+      #
+      # make a flake app that runs the test suite using cabal and the given
+      # version of ghc.  The ghc version is found in the nixpkgs
+      # `haskell.compiler` attribute set.
+      mkCabalTest = ghcVersion: {
         type = "app";
         program = "${
           pkgs.writeShellApplication {
             name = "cabal-build-and-test";
-            runtimeInputs = with pkgs; [pkg-config haskell.compiler.${ghcVersion} cabal-install];
+            runtimeInputs = with pkgs; [
+              pkg-config
+              haskell.compiler.${ghcVersion}
+              cabal-install
+            ];
 
             text = ''
               set -ex
@@ -53,6 +55,15 @@
           }
         }/bin/cabal-build-and-test";
       };
+    in {
+      checks = hslib.checks {};
+      devShells = hslib.devShells {};
+      packages = hslib.packages {};
+      apps.hlint = hslib.apps.hlint {};
+
+      # Using the working directory of `nix run`, do a build with cabal and
+      # then run the test suite.
+      apps.cabal-test-865 = mkCabalTest "ghc865Binary";
 
       apps.release = {
         type = "app";
diff --git a/tahoe-chk.cabal b/tahoe-chk.cabal
index 383af07df5aece4189e7c5c03ac3a1578681aab9..78ce5b2c9fe3975d71865b7e6a8b92760a7868d4 100644
--- a/tahoe-chk.cabal
+++ b/tahoe-chk.cabal
@@ -22,6 +22,8 @@ extra-source-files:
   ChangeLog.md
   README.md
 
+tested-with:        GHC ==8.6.5
+
 source-repository head
   type:     git
   location: