diff --git a/src/libexpr/tests/local.mk b/src/libexpr/tests/local.mk
index 6b766d82a..3e5504f71 100644
--- a/src/libexpr/tests/local.mk
+++ b/src/libexpr/tests/local.mk
@@ -14,6 +14,6 @@ libexpr-tests_SOURCES := \
 
 libexpr-tests_CXXFLAGS += -I src/libexpr -I src/libutil -I src/libstore -I src/libexpr/tests
 
-libexpr-tests_LIBS = libstore-tests libexpr libutil libstore libfetchers
+libexpr-tests_LIBS = libstore-tests libutils-tests libexpr libutil libstore libfetchers
 
 libexpr-tests_LDFLAGS := $(GTEST_LIBS) -lgmock
diff --git a/src/libexpr/tests/value/context.cc b/src/libexpr/tests/value/context.cc
index 0bcd79625..75934ab31 100644
--- a/src/libexpr/tests/value/context.cc
+++ b/src/libexpr/tests/value/context.cc
@@ -1,6 +1,10 @@
-#include "value/context.hh"
+#include <nlohmann/json.hpp>
+#include <gtest/gtest.h>
+#include <rapidcheck/gtest.h>
 
+#include "tests/path.hh"
 #include "tests/libexpr.hh"
+#include "tests/value/context.hh"
 
 namespace nix {
 
@@ -70,3 +74,39 @@ TEST_F(NixStringContextElemTest, built) {
 }
 
 }
+
+namespace rc {
+using namespace nix;
+
+Gen<NixStringContextElem> Arbitrary<NixStringContextElem>::arbitrary()
+{
+    switch (*gen::inRange<uint8_t>(0, 2)) {
+    case 0:
+        return gen::just((NixStringContextElem) NixStringContextElem::Opaque {
+            .path = *gen::arbitrary<StorePath>(),
+        });
+    case 1:
+        return gen::just((NixStringContextElem) NixStringContextElem::DrvDeep {
+            .drvPath = *gen::arbitrary<StorePath>(),
+        });
+    default:
+        return gen::just((NixStringContextElem) NixStringContextElem::Built {
+            .drvPath = *gen::arbitrary<StorePath>(),
+            .output = (*gen::arbitrary<StorePathName>()).name,
+        });
+    }
+}
+
+}
+
+namespace nix {
+
+RC_GTEST_FIXTURE_PROP(
+    NixStringContextElemTest,
+    prop_round_rip,
+    (const NixStringContextElem & o))
+{
+    RC_ASSERT(o == NixStringContextElem::parse(store(), o.to_string(store())));
+}
+
+}
diff --git a/src/libexpr/tests/value/context.hh b/src/libexpr/tests/value/context.hh
new file mode 100644
index 000000000..83505962f
--- /dev/null
+++ b/src/libexpr/tests/value/context.hh
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <rapidcheck/gen/Arbitrary.h>
+
+#include <value/context.hh>
+
+namespace rc {
+using namespace nix;
+
+template<>
+struct Arbitrary<NixStringContextElem> {
+    static Gen<NixStringContextElem> arbitrary();
+};
+
+}
diff --git a/src/libexpr/value/context.hh b/src/libexpr/value/context.hh
index d8008c436..721563cba 100644
--- a/src/libexpr/value/context.hh
+++ b/src/libexpr/value/context.hh
@@ -1,9 +1,10 @@
 #pragma once
 
 #include "util.hh"
+#include "comparator.hh"
 #include "path.hh"
 
-#include <optional>
+#include <variant>
 
 #include <nlohmann/json_fwd.hpp>
 
@@ -31,7 +32,9 @@ class Store;
    Encoded as just the path: ‘<path>’.
 */
 struct NixStringContextElem_Opaque {
-   StorePath path;
+    StorePath path;
+
+    GENERATE_CMP(NixStringContextElem_Opaque, me->path);
 };
 
 /* Path to a derivation and its entire build closure.
@@ -43,7 +46,9 @@ struct NixStringContextElem_Opaque {
    Encoded in the form ‘=<drvPath>’.
 */
 struct NixStringContextElem_DrvDeep {
-   StorePath drvPath;
+    StorePath drvPath;
+
+    GENERATE_CMP(NixStringContextElem_DrvDeep, me->drvPath);
 };
 
 /* Derivation output.
@@ -51,8 +56,10 @@ struct NixStringContextElem_DrvDeep {
    Encoded in the form ‘!<output>!<drvPath>’.
 */
 struct NixStringContextElem_Built {
-   StorePath drvPath;
-   std::string output;
+    StorePath drvPath;
+    std::string output;
+
+    GENERATE_CMP(NixStringContextElem_Built, me->drvPath, me->output);
 };
 
 using _NixStringContextElem_Raw = std::variant<
diff --git a/src/libstore/derived-path.hh b/src/libstore/derived-path.hh
index 4edff7467..9e0cce377 100644
--- a/src/libstore/derived-path.hh
+++ b/src/libstore/derived-path.hh
@@ -4,8 +4,9 @@
 #include "path.hh"
 #include "realisation.hh"
 #include "outputs-spec.hh"
+#include "comparator.hh"
 
-#include <optional>
+#include <variant>
 
 #include <nlohmann/json_fwd.hpp>
 
@@ -27,8 +28,7 @@ struct DerivedPathOpaque {
     std::string to_string(const Store & store) const;
     static DerivedPathOpaque parse(const Store & store, std::string_view);
 
-    bool operator < (const DerivedPathOpaque & b) const
-    { return path < b.path; }
+    GENERATE_CMP(DerivedPathOpaque, me->path);
 };
 
 /**
@@ -51,8 +51,7 @@ struct DerivedPathBuilt {
     static DerivedPathBuilt parse(const Store & store, std::string_view, std::string_view);
     nlohmann::json toJSON(ref<Store> store) const;
 
-    bool operator < (const DerivedPathBuilt & b) const
-    { return std::make_pair(drvPath, outputs) < std::make_pair(b.drvPath, b.outputs); }
+    GENERATE_CMP(DerivedPathBuilt, me->drvPath, me->outputs);
 };
 
 using _DerivedPathRaw = std::variant<
@@ -96,6 +95,8 @@ struct BuiltPathBuilt {
 
     nlohmann::json toJSON(ref<Store> store) const;
     static BuiltPathBuilt parse(const Store & store, std::string_view);
+
+    GENERATE_CMP(BuiltPathBuilt, me->drvPath, me->outputs);
 };
 
 using _BuiltPathRaw = std::variant<
diff --git a/src/libstore/tests/derived-path.cc b/src/libstore/tests/derived-path.cc
new file mode 100644
index 000000000..09887d1f0
--- /dev/null
+++ b/src/libstore/tests/derived-path.cc
@@ -0,0 +1,52 @@
+#include <regex>
+
+#include <nlohmann/json.hpp>
+#include <gtest/gtest.h>
+#include <rapidcheck/gtest.h>
+
+#include "tests/derived-path.hh"
+#include "tests/libstore.hh"
+
+namespace rc {
+using namespace nix;
+
+Gen<DerivedPath> Arbitrary<DerivedPath>::arbitrary()
+{
+    switch (*gen::inRange<uint8_t>(0, 1)) {
+    case 0:
+        return gen::just((DerivedPath) DerivedPath::Opaque {
+            .path = *gen::arbitrary<StorePath>(),
+        });
+    default:
+        return gen::just((DerivedPath) DerivedPath::Built {
+            .drvPath = *gen::arbitrary<StorePath>(),
+            .outputs = *gen::arbitrary<OutputsSpec>(),
+        });
+    }
+}
+
+}
+
+namespace nix {
+
+class DerivedPathTest : public LibStoreTest
+{
+};
+
+// FIXME: `RC_GTEST_FIXTURE_PROP` isn't calling `SetUpTestSuite` because it is
+// no a real fixture.
+//
+// See https://github.com/emil-e/rapidcheck/blob/master/doc/gtest.md#rc_gtest_fixture_propfixture-name-args
+TEST_F(DerivedPathTest, force_init)
+{
+}
+
+RC_GTEST_FIXTURE_PROP(
+    DerivedPathTest,
+    prop_round_rip,
+    (const DerivedPath & o))
+{
+    RC_ASSERT(o == DerivedPath::parse(*store, o.to_string(*store)));
+}
+
+}
diff --git a/src/libstore/tests/derived-path.hh b/src/libstore/tests/derived-path.hh
new file mode 100644
index 000000000..0161449ef
--- /dev/null
+++ b/src/libstore/tests/derived-path.hh
@@ -0,0 +1,18 @@
+#pragma once
+
+#include <rapidcheck/gen/Arbitrary.h>
+
+#include <derived-path.hh>
+
+#include "tests/path.hh"
+#include "tests/outputs-spec.hh"
+
+namespace rc {
+using namespace nix;
+
+template<>
+struct Arbitrary<DerivedPath> {
+    static Gen<DerivedPath> arbitrary();
+};
+
+}
diff --git a/src/libstore/tests/local.mk b/src/libstore/tests/local.mk
index c24712ccf..03becc7d1 100644
--- a/src/libstore/tests/local.mk
+++ b/src/libstore/tests/local.mk
@@ -24,6 +24,6 @@ libstore-tests_SOURCES := $(wildcard $(d)/*.cc)
 
 libstore-tests_CXXFLAGS += -I src/libstore -I src/libutil
 
-libstore-tests_LIBS = libstore libutil
+libstore-tests_LIBS = libutil-tests libstore libutil
 
 libstore-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS)
diff --git a/src/libstore/tests/outputs-spec.cc b/src/libstore/tests/outputs-spec.cc
index 06e4cabbd..984d1d963 100644
--- a/src/libstore/tests/outputs-spec.cc
+++ b/src/libstore/tests/outputs-spec.cc
@@ -2,6 +2,7 @@
 
 #include <nlohmann/json.hpp>
 #include <gtest/gtest.h>
+#include <rapidcheck/gtest.h>
 
 namespace nix {
 
@@ -199,3 +200,34 @@ TEST_JSON(ExtendedOutputsSpec, names, R"(["a","b"])", (ExtendedOutputsSpec::Expl
 #undef TEST_JSON
 
 }
+
+namespace rc {
+using namespace nix;
+
+Gen<OutputsSpec> Arbitrary<OutputsSpec>::arbitrary()
+{
+    switch (*gen::inRange<uint8_t>(0, 1)) {
+    case 0:
+        return gen::just((OutputsSpec) OutputsSpec::All { });
+    default:
+        return gen::just((OutputsSpec) OutputsSpec::Names {
+            *gen::nonEmpty(gen::container<StringSet>(gen::map(
+                gen::arbitrary<StorePathName>(),
+                [](StorePathName n) { return n.name; }))),
+        });
+    }
+}
+
+}
+
+namespace nix {
+
+RC_GTEST_PROP(
+    OutputsSpec,
+    prop_round_rip,
+    (const OutputsSpec & o))
+{
+    RC_ASSERT(o == OutputsSpec::parse(o.to_string()));
+}
+
+}
diff --git a/src/libstore/tests/outputs-spec.hh b/src/libstore/tests/outputs-spec.hh
new file mode 100644
index 000000000..2d455c817
--- /dev/null
+++ b/src/libstore/tests/outputs-spec.hh
@@ -0,0 +1,17 @@
+#pragma once
+
+#include <rapidcheck/gen/Arbitrary.h>
+
+#include <outputs-spec.hh>
+
+#include <tests/path.hh>
+
+namespace rc {
+using namespace nix;
+
+template<>
+struct Arbitrary<OutputsSpec> {
+    static Gen<OutputsSpec> arbitrary();
+};
+
+}
diff --git a/src/libstore/tests/path.cc b/src/libstore/tests/path.cc
index 2fc6d7e48..430aa0099 100644
--- a/src/libstore/tests/path.cc
+++ b/src/libstore/tests/path.cc
@@ -7,6 +7,7 @@
 #include "path-regex.hh"
 #include "store-api.hh"
 
+#include "tests/hash.hh"
 #include "tests/libstore.hh"
 #include "tests/path.hh"
 
@@ -74,12 +75,14 @@ void showValue(const StorePath & p, std::ostream & os) {
 namespace rc {
 using namespace nix;
 
-Gen<StorePath> Arbitrary<StorePath>::arbitrary()
+Gen<StorePathName> Arbitrary<StorePathName>::arbitrary()
 {
-    auto len = *gen::inRange<size_t>(1, StorePath::MaxPathLen);
+    auto len = *gen::inRange<size_t>(
+        1,
+        StorePath::MaxPathLen - std::string_view { HASH_PART }.size());
 
-    std::string pre { HASH_PART "-" };
-    pre.reserve(pre.size() + len);
+    std::string pre;
+    pre.reserve(len);
 
     for (size_t c = 0; c < len; ++c) {
         switch (auto i = *gen::inRange<uint8_t>(0, 10 + 2 * 26 + 6)) {
@@ -114,7 +117,17 @@ Gen<StorePath> Arbitrary<StorePath>::arbitrary()
         }
     }
 
-    return gen::just(StorePath { pre });
+    return gen::just(StorePathName {
+        .name = std::move(pre),
+    });
+}
+
+Gen<StorePath> Arbitrary<StorePath>::arbitrary()
+{
+    return gen::just(StorePath {
+        *gen::arbitrary<Hash>(),
+        (*gen::arbitrary<StorePathName>()).name,
+    });
 }
 
 } // namespace rc
diff --git a/src/libstore/tests/path.hh b/src/libstore/tests/path.hh
index 0ac9bb9f2..d7f1a8988 100644
--- a/src/libstore/tests/path.hh
+++ b/src/libstore/tests/path.hh
@@ -1,12 +1,25 @@
 #pragma once
 
-#include <rapidcheck.h>
+#include <rapidcheck/gen/Arbitrary.h>
 
-#include "path.hh"
+#include <path.hh>
+
+namespace nix {
+
+struct StorePathName {
+    std::string name;
+};
+
+}
 
 namespace rc {
 using namespace nix;
 
+template<>
+struct Arbitrary<StorePathName> {
+    static Gen<StorePathName> arbitrary();
+};
+
 template<>
 struct Arbitrary<StorePath> {
     static Gen<StorePath> arbitrary();
diff --git a/src/libutil/tests/hash.cc b/src/libutil/tests/hash.cc
index 412c03030..e4e928b3b 100644
--- a/src/libutil/tests/hash.cc
+++ b/src/libutil/tests/hash.cc
@@ -1,5 +1,12 @@
-#include "hash.hh"
+#include <regex>
+
+#include <nlohmann/json.hpp>
 #include <gtest/gtest.h>
+#include <rapidcheck/gtest.h>
+
+#include <hash.hh>
+
+#include "tests/hash.hh"
 
 namespace nix {
 
@@ -73,3 +80,16 @@ namespace nix {
                 "c7d329eeb6dd26545e96e55b874be909");
     }
 }
+
+namespace rc {
+using namespace nix;
+
+Gen<Hash> Arbitrary<Hash>::arbitrary()
+{
+    Hash hash(htSHA1);
+    for (size_t i = 0; i < hash.hashSize; ++i)
+        hash.hash[i] = *gen::arbitrary<uint8_t>();
+    return gen::just(hash);
+}
+
+}
diff --git a/src/libutil/tests/hash.hh b/src/libutil/tests/hash.hh
new file mode 100644
index 000000000..9e9650e6e
--- /dev/null
+++ b/src/libutil/tests/hash.hh
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <rapidcheck/gen/Arbitrary.h>
+
+#include <hash.hh>
+
+namespace rc {
+using namespace nix;
+
+template<>
+struct Arbitrary<Hash> {
+    static Gen<Hash> arbitrary();
+};
+
+}
diff --git a/src/libutil/tests/local.mk b/src/libutil/tests/local.mk
index 4f2a3f294..167915439 100644
--- a/src/libutil/tests/local.mk
+++ b/src/libutil/tests/local.mk
@@ -2,7 +2,19 @@ check: libutil-tests_RUN
 
 programs += libutil-tests
 
-libutil-tests_NAME := libnixutil-tests
+libutil-tests-exe_NAME = libnixutil-tests
+
+libutil-tests-exe_DIR := $(d)
+
+libutil-tests-exe_INSTALL_DIR :=
+
+libutil-tests-exe_LIBS = libutil-tests
+
+libutil-tests-exe_LDFLAGS := $(GTEST_LIBS)
+
+libraries += libutil-tests
+
+libutil-tests_NAME = libnixutil-tests
 
 libutil-tests_DIR := $(d)
 
@@ -10,8 +22,8 @@ libutil-tests_INSTALL_DIR :=
 
 libutil-tests_SOURCES := $(wildcard $(d)/*.cc)
 
-libutil-tests_CXXFLAGS += -I src/libutil -I src/libexpr
+libutil-tests_CXXFLAGS += -I src/libutil
 
 libutil-tests_LIBS = libutil
 
-libutil-tests_LDFLAGS := $(GTEST_LIBS)
+libutil-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS)