Remove (bugggy) no-tests workarounds

The no-coverage-report special case hid real coverage build failures
unintentionally.

Author: nothingmuch

nix/checks.nix

@@ -28,7 +28,6 @@
           strictDeps = true;
           cargoArtifacts = deps;
           CARGO_PROFILE = profile;
-          cargoNextestExtraArgs = "--no-tests=warn";
         };
 
       testChecks = pkgs.lib.concatMapAttrs (
@@ -51,14 +50,7 @@
             nativeBuildInputs = [ pkgs.cargo-llvm-cov ];
             buildPhaseCargoCommand = ''
               mkdir -p $out
-              cargo llvm-cov --all-features --lcov --output-path $out/coverage.lcov || {
-                # no coverage data when there are no tests yet
-                if [ ! -s $out/coverage.lcov ]; then
-                  echo "no coverage data (no tests), skipping assertion"
-                  exit 0
-                fi
-                exit 1
-              }
+              cargo llvm-cov --all-features --lcov --output-path $out/coverage.lcov
               cargo llvm-cov report --fail-under-regions 100
             '';
             installPhase = "true";