diff --git a/flake.nix b/flake.nix
index ba526a9b8..fc46ef940 100644
--- a/flake.nix
+++ b/flake.nix
@@ -334,6 +334,10 @@
             ++ lib.optional (stdenv.cc.isClang && stdenv.hostPlatform == stdenv.buildPlatform) pkgs.buildPackages.clang-tools;
 
           buildInputs = attrs.buildInputs or []
+            ++ [
+              pkgs.gtest
+              pkgs.rapidcheck
+            ]
             ++ lib.optional havePerl pkgs.perl
             ;
         });
diff --git a/packaging/components.nix b/packaging/components.nix
index 97b989f1f..5576877cb 100644
--- a/packaging/components.nix
+++ b/packaging/components.nix
@@ -8,28 +8,26 @@ in
   nix = callPackage ../package.nix { };
 
   nix-util = callPackage ../src/libutil/package.nix { };
+  nix-util-c = callPackage ../src/libutil-c/package.nix { };
   nix-util-test-support = callPackage ../src/libutil-test-support/package.nix { };
   nix-util-test = callPackage ../src/libutil-test/package.nix { };
-  nix-util-c = callPackage ../src/libutil-c/package.nix { };
 
   nix-store = callPackage ../src/libstore/package.nix { };
+  nix-store-c = callPackage ../src/libstore-c/package.nix { };
   nix-store-test-support = callPackage ../src/libstore-test-support/package.nix { };
   nix-store-test = callPackage ../src/libstore-test/package.nix { };
-  nix-store-c = callPackage ../src/libstore-c/package.nix { };
 
   nix-fetchers = callPackage ../src/libfetchers/package.nix { };
   nix-fetchers-test = callPackage ../src/libfetchers-test/package.nix { };
-  nix-fetchers-c = callPackage ../src/libfetchers-c/package.nix { };
 
   nix-expr = callPackage ../src/libexpr/package.nix { };
+  nix-expr-c = callPackage ../src/libexpr-c/package.nix { };
   nix-expr-test-support = callPackage ../src/libexpr-test-support/package.nix { };
   nix-expr-test = callPackage ../src/libexpr-test/package.nix { };
-  nix-expr-c = callPackage ../src/libexpr-c/package.nix { };
 
   nix-flake = callPackage ../src/libflake/package.nix { };
 
   nix-internal-api-docs = callPackage ../src/internal-api-docs/package.nix { };
-
   nix-external-api-docs = callPackage ../src/external-api-docs/package.nix { };
 
   nix-perl-bindings = callPackage ../src/perl/package.nix { };
diff --git a/src/libexpr-c/package.nix b/src/libexpr-c/package.nix
index ce86780c1..542be064d 100644
--- a/src/libexpr-c/package.nix
+++ b/src/libexpr-c/package.nix
@@ -41,7 +41,7 @@ mkDerivation (finalAttrs: {
     root = ./.;
     fileset = fileset.unions [
       ./meson.build
-      ./meson.options
+      # ./meson.options
       (fileset.fileFilter (file: file.hasExt "cc") ./.)
       (fileset.fileFilter (file: file.hasExt "hh") ./.)
       (fileset.fileFilter (file: file.hasExt "h") ./.)
diff --git a/src/libexpr-test/meson.build b/src/libexpr-test/meson.build
index e5bb771e3..cc32b0a1a 100644
--- a/src/libexpr-test/meson.build
+++ b/src/libexpr-test/meson.build
@@ -39,6 +39,9 @@ deps_private += rapidcheck
 gtest = dependency('gtest', main : true)
 deps_private += gtest
 
+gtest = dependency('gmock')
+deps_private += gtest
+
 add_project_arguments(
   # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
   # It would be nice for our headers to be idempotent instead.
diff --git a/src/libexpr/package.nix b/src/libexpr/package.nix
index 799368ee9..14fbf0a06 100644
--- a/src/libexpr/package.nix
+++ b/src/libexpr/package.nix
@@ -85,7 +85,7 @@ mkDerivation (finalAttrs: {
     '';
 
   mesonFlags = [
-    (lib.mesonFeature "gc" enableGC)
+    (lib.mesonEnable "gc" enableGC)
   ];
 
   env = {
diff --git a/src/libfetchers-test/package.nix b/src/libfetchers-test/package.nix
new file mode 100644
index 000000000..f4d3f3b73
--- /dev/null
+++ b/src/libfetchers-test/package.nix
@@ -0,0 +1,111 @@
+{ lib
+, stdenv
+, releaseTools
+
+, meson
+, ninja
+, pkg-config
+
+, nix-fetchers
+, nix-store-test-support
+
+, rapidcheck
+, gtest
+, runCommand
+
+# Configuration Options
+
+, versionSuffix ? ""
+
+# Check test coverage of Nix. Probably want to use with at least
+# one of `doCheck` or `doInstallCheck` enabled.
+, withCoverageChecks ? false
+}:
+
+let
+  inherit (lib) fileset;
+
+  version = lib.fileContents ./.version + versionSuffix;
+
+  mkDerivation =
+    if withCoverageChecks
+    then
+      # TODO support `finalAttrs` args function in
+      # `releaseTools.coverageAnalysis`.
+      argsFun:
+         releaseTools.coverageAnalysis (let args = argsFun args; in args)
+    else stdenv.mkDerivation;
+in
+
+mkDerivation (finalAttrs: {
+  pname = "nix-fetchers-test";
+  inherit version;
+
+  src = fileset.toSource {
+    root = ./.;
+    fileset = fileset.unions [
+      ./meson.build
+      # ./meson.options
+      (fileset.fileFilter (file: file.hasExt "cc") ./.)
+      (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    ];
+  };
+
+  outputs = [ "out" "dev" ];
+
+  nativeBuildInputs = [
+    meson
+    ninja
+    pkg-config
+  ];
+
+  buildInputs = [
+    nix-fetchers
+    nix-store-test-support
+    rapidcheck
+    gtest
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix
+    ''
+      echo ${version} > .version
+    '';
+
+  mesonFlags = [
+  ];
+
+  env = lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  enableParallelBuilding = true;
+
+  separateDebugInfo = !stdenv.hostPlatform.isStatic;
+
+  # TODO Always true after https://github.com/NixOS/nixpkgs/issues/318564
+  strictDeps = !withCoverageChecks;
+
+  hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
+
+  passthru = {
+    tests = {
+      run = runCommand "${finalAttrs.pname}-run" {
+      } ''
+        PATH="${lib.makeBinPath [ finalAttrs.finalPackage ]}:$PATH"
+        export _NIX_TEST_UNIT_DATA=${./data}
+        nix-fetchers-test
+        touch $out
+      '';
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+} // lib.optionalAttrs withCoverageChecks {
+  lcovFilter = [ "*/boost/*" "*-tab.*" ];
+
+  hardeningDisable = [ "fortify" ];
+})
diff --git a/src/libflake-test/package.nix b/src/libflake-test/package.nix
new file mode 100644
index 000000000..f03f58619
--- /dev/null
+++ b/src/libflake-test/package.nix
@@ -0,0 +1,111 @@
+{ lib
+, stdenv
+, releaseTools
+
+, meson
+, ninja
+, pkg-config
+
+, nix-flake
+, nix-expr-test-support
+
+, rapidcheck
+, gtest
+, runCommand
+
+# Configuration Options
+
+, versionSuffix ? ""
+
+# Check test coverage of Nix. Probably want to use with at least
+# one of `doCheck` or `doInstallCheck` enabled.
+, withCoverageChecks ? false
+}:
+
+let
+  inherit (lib) fileset;
+
+  version = lib.fileContents ./.version + versionSuffix;
+
+  mkDerivation =
+    if withCoverageChecks
+    then
+      # TODO support `finalAttrs` args function in
+      # `releaseTools.coverageAnalysis`.
+      argsFun:
+         releaseTools.coverageAnalysis (let args = argsFun args; in args)
+    else stdenv.mkDerivation;
+in
+
+mkDerivation (finalAttrs: {
+  pname = "nix-flake-test";
+  inherit version;
+
+  src = fileset.toSource {
+    root = ./.;
+    fileset = fileset.unions [
+      ./meson.build
+      # ./meson.options
+      (fileset.fileFilter (file: file.hasExt "cc") ./.)
+      (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    ];
+  };
+
+  outputs = [ "out" "dev" ];
+
+  nativeBuildInputs = [
+    meson
+    ninja
+    pkg-config
+  ];
+
+  buildInputs = [
+    nix-flake
+    nix-expr-test-support
+    rapidcheck
+    gtest
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix
+    ''
+      echo ${version} > .version
+    '';
+
+  mesonFlags = [
+  ];
+
+  env = lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  enableParallelBuilding = true;
+
+  separateDebugInfo = !stdenv.hostPlatform.isStatic;
+
+  # TODO Always true after https://github.com/NixOS/nixpkgs/issues/318564
+  strictDeps = !withCoverageChecks;
+
+  hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
+
+  passthru = {
+    tests = {
+      run = runCommand "${finalAttrs.pname}-run" {
+      } ''
+        PATH="${lib.makeBinPath [ finalAttrs.finalPackage ]}:$PATH"
+        export _NIX_TEST_UNIT_DATA=${./data}
+        nix-flake-test
+        touch $out
+      '';
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+} // lib.optionalAttrs withCoverageChecks {
+  lcovFilter = [ "*/boost/*" "*-tab.*" ];
+
+  hardeningDisable = [ "fortify" ];
+})
diff --git a/src/libstore-c/package.nix b/src/libstore-c/package.nix
index aedbad4a2..2ed78a760 100644
--- a/src/libstore-c/package.nix
+++ b/src/libstore-c/package.nix
@@ -41,7 +41,7 @@ mkDerivation (finalAttrs: {
     root = ./.;
     fileset = fileset.unions [
       ./meson.build
-      ./meson.options
+      # ./meson.options
       (fileset.fileFilter (file: file.hasExt "cc") ./.)
       (fileset.fileFilter (file: file.hasExt "hh") ./.)
       (fileset.fileFilter (file: file.hasExt "h") ./.)
diff --git a/src/libstore-test/meson.build b/src/libstore-test/meson.build
index cb561977c..2cdbfa7b5 100644
--- a/src/libstore-test/meson.build
+++ b/src/libstore-test/meson.build
@@ -36,6 +36,9 @@ deps_private += rapidcheck
 gtest = dependency('gtest', main : true)
 deps_private += gtest
 
+gtest = dependency('gmock')
+deps_private += gtest
+
 add_project_arguments(
   # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
   # It would be nice for our headers to be idempotent instead.