diff --git a/flake.nix b/flake.nix
index 249da2a04..dfb2dc1f8 100644
--- a/flake.nix
+++ b/flake.nix
@@ -588,6 +588,8 @@
             lcovFilter = [ "*/boost/*" "*-tab.*" ];
 
             hardeningDisable = ["fortify"];
+
+            NIX_CFLAGS_COMPILE = "-DCOVERAGE=1";
           };
 
         # API docs for Nix's unstable internal C++ interfaces.
diff --git a/src/libexpr/tests/derived-path.cc b/src/libexpr/tests/derived-path.cc
index d01735db8..d5fc6f201 100644
--- a/src/libexpr/tests/derived-path.cc
+++ b/src/libexpr/tests/derived-path.cc
@@ -18,6 +18,8 @@ TEST_F(DerivedPathExpressionTest, force_init)
 {
 }
 
+#ifndef COVERAGE
+
 RC_GTEST_FIXTURE_PROP(
     DerivedPathExpressionTest,
     prop_opaque_path_round_trip,
@@ -61,4 +63,6 @@ RC_GTEST_FIXTURE_PROP(
     RC_ASSERT(SingleDerivedPath { b } == d);
 }
 
+#endif
+
 } /* namespace nix */
diff --git a/src/libexpr/tests/value/context.cc b/src/libexpr/tests/value/context.cc
index 19407d071..92d4889ab 100644
--- a/src/libexpr/tests/value/context.cc
+++ b/src/libexpr/tests/value/context.cc
@@ -147,6 +147,8 @@ Gen<NixStringContextElem> Arbitrary<NixStringContextElem>::arbitrary()
 
 namespace nix {
 
+#ifndef COVERAGE
+
 RC_GTEST_PROP(
     NixStringContextElemTest,
     prop_round_rip,
@@ -155,4 +157,6 @@ RC_GTEST_PROP(
     RC_ASSERT(o == NixStringContextElem::parse(o.to_string()));
 }
 
+#endif
+
 }
diff --git a/src/libstore/tests/derived-path.cc b/src/libstore/tests/derived-path.cc
index d6549f66f..3fa3c0801 100644
--- a/src/libstore/tests/derived-path.cc
+++ b/src/libstore/tests/derived-path.cc
@@ -130,6 +130,8 @@ TEST_F(DerivedPathTest, built_built_xp) {
         MissingExperimentalFeature);
 }
 
+#ifndef COVERAGE
+
 RC_GTEST_FIXTURE_PROP(
     DerivedPathTest,
     prop_legacy_round_rip,
@@ -146,4 +148,6 @@ RC_GTEST_FIXTURE_PROP(
     RC_ASSERT(o == DerivedPath::parse(*store, o.to_string(*store)));
 }
 
+#endif
+
 }
diff --git a/src/libstore/tests/outputs-spec.cc b/src/libstore/tests/outputs-spec.cc
index bf8deaa9d..952945185 100644
--- a/src/libstore/tests/outputs-spec.cc
+++ b/src/libstore/tests/outputs-spec.cc
@@ -224,6 +224,8 @@ Gen<OutputsSpec> Arbitrary<OutputsSpec>::arbitrary()
 
 namespace nix {
 
+#ifndef COVERAGE
+
 RC_GTEST_PROP(
     OutputsSpec,
     prop_round_rip,
@@ -232,4 +234,6 @@ RC_GTEST_PROP(
     RC_ASSERT(o == OutputsSpec::parse(o.to_string()));
 }
 
+#endif
+
 }
diff --git a/src/libstore/tests/path.cc b/src/libstore/tests/path.cc
index 430aa0099..efa35ef2b 100644
--- a/src/libstore/tests/path.cc
+++ b/src/libstore/tests/path.cc
@@ -134,6 +134,8 @@ Gen<StorePath> Arbitrary<StorePath>::arbitrary()
 
 namespace nix {
 
+#ifndef COVERAGE
+
 RC_GTEST_FIXTURE_PROP(
     StorePathTest,
     prop_regex_accept,
@@ -150,4 +152,6 @@ RC_GTEST_FIXTURE_PROP(
     RC_ASSERT(p == store->parseStorePath(store->printStorePath(p)));
 }
 
+#endif
+
 }