Merge pull request #8923 from obsidiansystems/test-proto

Unit test some worker protocol serializers

(cherry picked from commit c6faef61a6f31c71146aee5d88168e861df9a22a)
Change-Id: I99e36f5f17eb7642211a4e42a16b143424f164b4

11 files changed, 222 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index 41c0ab68a..e0be7cdcd 100644
--- a/Makefile
+++ b/Makefile
@@ -22,6 +22,7 @@ makefiles = \
 -include Makefile.config
 
 ifeq ($(tests), yes)
+UNIT_TEST_ENV = _NIX_TEST_UNIT_DATA=unit-test-data
 makefiles += \
   tests/unit/libutil/local.mk \
   tests/unit/libutil-support/local.mk \
diff --git a/doc/manual/src/contributing/testing.md b/doc/manual/src/contributing/testing.md
index 1b15d12b1..6f954ac68 100644
--- a/doc/manual/src/contributing/testing.md
+++ b/doc/manual/src/contributing/testing.md
@@ -2,10 +2,48 @@
 
 ## Unit-tests
 
-The unit-tests for each Nix library (`libexpr`, `libstore`, etc..) are defined
-under `tests/unit/{library_name}/tests` using the
-[googletest](https://google.github.io/googletest/) and
-[rapidcheck](https://github.com/emil-e/rapidcheck) frameworks.
+The unit tests are defined using the [googletest] and [rapidcheck] frameworks.
+
+[googletest]: https://google.github.io/googletest/
+[rapidcheck]: https://github.com/emil-e/rapidcheck
+
+### Source and header layout
+
+> An example of some files, demonstrating much of what is described below
+>
+> ```
+> src
+> ├── libexpr
+> │   ├── value/context.hh
+> │   ├── value/context.cc
+> │   │
+> │   …
+>     └── tests
+> │       ├── value/context.hh
+> │       ├── value/context.cc
+> │       │
+> │       …
+> │
+> ├── unit-test-data
+> │   ├── libstore
+> │   │   ├── worker-protocol/content-address.bin
+> │   │   …
+> │   …
+> …
+> ```
+
+The unit tests for each Nix library (`libnixexpr`, `libnixstore`, etc..) live inside a directory `src/${library_shortname}/tests` within the directory for the library (`src/${library_shortname}`).
+
+The data is in `unit-test-data`, with one subdir per library, with the same name as where the code goes.
+For example, `libnixstore` code is in `src/libstore`, and its test data is in `unit-test-data/libstore`.
+The path to the `unit-test-data` directory is passed to the unit test executable with the environment variable `_NIX_TEST_UNIT_DATA`.
+
+> **Note**
+> Due to the way googletest works, downstream unit test executables will actually include and re-run upstream library tests.
+> Therefore it is important that the same value for `_NIX_TEST_UNIT_DATA` be used with the tests for each library.
+> That is why we have the test data nested within a single `unit-test-data` directory.
+
+### Running tests
 
 You can run the whole testsuite with `make check`, or the tests for a specific component with `make libfoo-tests_RUN`.
 Finer-grained filtering is also possible using the [--gtest_filter](https://google.github.io/googletest/advanced.html#running-a-subset-of-the-tests) command-line option, or the `GTEST_FILTER` environment variable.
@@ -22,6 +60,24 @@ It is important that these testing libraries don't contain any actual tests them
 On some platforms they would be run as part of every test executable that uses them, which is redundant.
 On other platforms they wouldn't be run at all.
 
+### Characterization testing
+
+See [below](#characterization-testing-1) for a broader discussion of characterization testing.
+
+Like with the functional characterization, `_NIX_TEST_ACCEPT=1` is also used.
+For example:
+```shell-session
+$ _NIX_TEST_ACCEPT=1 make libstore-tests-exe_RUN
+...
+[  SKIPPED ] WorkerProtoTest.string_read
+[  SKIPPED ] WorkerProtoTest.string_write
+[  SKIPPED ] WorkerProtoTest.storePath_read
+[  SKIPPED ] WorkerProtoTest.storePath_write
+...
+```
+will regenerate the "golden master" expected result for the `libnixstore` characterization tests.
+The characterization tests will mark themselves "skipped" since they regenerated the expected result instead of actually testing anything.
+
 ## Functional tests
 
 The functional tests reside under the `tests/functional` directory and are listed in `tests/functional/local.mk`.
diff --git a/flake.nix b/flake.nix
index 0722d4a5b..ac1d0606a 100644
--- a/flake.nix
+++ b/flake.nix
@@ -77,6 +77,7 @@
           ./src
           ./tests/functional
           ./tests/unit
+          ./unit-test-data
           ./COPYING
           ./scripts/local.mk
           (fileset.fileFilter (f: lib.strings.hasPrefix "nix-profile" f.name) ./scripts)
diff --git a/mk/programs.mk b/mk/programs.mk
index 1ee1d3fa5..a88d9d949 100644
--- a/mk/programs.mk
+++ b/mk/programs.mk
@@ -87,6 +87,6 @@ define build-program
   # Phony target to run this program (typically as a dependency of 'check').
   .PHONY: $(1)_RUN
   $(1)_RUN: $$($(1)_PATH)
-	$(trace-test) $$($(1)_PATH)
+	$(trace-test) $$(UNIT_TEST_ENV) $$($(1)_PATH)
 
 endef
diff --git a/src/libstore/worker-protocol-impl.hh b/src/libstore/worker-protocol-impl.hh
index d3d2792ff..4f797f95a 100644
--- a/src/libstore/worker-protocol-impl.hh
+++ b/src/libstore/worker-protocol-impl.hh
@@ -75,4 +75,20 @@ void WorkerProto::Serialise<std::map<K, V>>::write(const Store & store, WorkerPr
     }
 }
 
+template<typename... Ts>
+std::tuple<Ts...> WorkerProto::Serialise<std::tuple<Ts...>>::read(const Store & store, WorkerProto::ReadConn conn)
+{
+    return std::tuple<Ts...> {
+        WorkerProto::Serialise<Ts>::read(store, conn)...,
+    };
+}
+
+template<typename... Ts>
+void WorkerProto::Serialise<std::tuple<Ts...>>::write(const Store & store, WorkerProto::WriteConn conn, const std::tuple<Ts...> & res)
+{
+    std::apply([&]<typename... Us>(const Us &... args) {
+        (WorkerProto::Serialise<Us>::write(store, conn, args), ...);
+    }, res);
+}
+
 }
diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh
index ff762c924..70a5bddb9 100644
--- a/src/libstore/worker-protocol.hh
+++ b/src/libstore/worker-protocol.hh
@@ -28,6 +28,8 @@ class Store;
 struct Source;
 
 // items being serialised
+class StorePath;
+struct ContentAddress;
 struct DerivedPath;
 struct DrvOutput;
 struct Realisation;
@@ -220,6 +222,8 @@ template<typename T>
 MAKE_WORKER_PROTO(std::vector<T>);
 template<typename T>
 MAKE_WORKER_PROTO(std::set<T>);
+template<typename... Ts>
+MAKE_WORKER_PROTO(std::tuple<Ts...>);
 
 template<typename K, typename V>
 #define X_ std::map<K, V>
diff --git a/tests/unit/libstore/worker-protocol.cc b/tests/unit/libstore/worker-protocol.cc
new file mode 100644
index 000000000..4a6ccf7c0
--- /dev/null
+++ b/tests/unit/libstore/worker-protocol.cc
@@ -0,0 +1,139 @@
+#include <regex>
+
+#include <nlohmann/json.hpp>
+#include <gtest/gtest.h>
+
+#include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
+#include "derived-path.hh"
+#include "tests/libstore.hh"
+
+namespace nix {
+
+class WorkerProtoTest : public LibStoreTest
+{
+public:
+    Path unitTestData = getEnv("_NIX_TEST_UNIT_DATA").value() + "/libstore/worker-protocol";
+
+    bool testAccept() {
+        return getEnv("_NIX_TEST_ACCEPT") == "1";
+    }
+
+    Path goldenMaster(std::string_view testStem) {
+        return unitTestData + "/" + testStem + ".bin";
+    }
+
+    /**
+     * Golden test for `T` reading
+     */
+    template<typename T>
+    void readTest(PathView testStem, T value)
+    {
+        if (testAccept())
+        {
+            GTEST_SKIP() << "Cannot read golden master because another test is also updating it";
+        }
+        else
+        {
+            auto expected = readFile(goldenMaster(testStem));
+
+            T got = ({
+                StringSource from { expected };
+                WorkerProto::Serialise<T>::read(
+                    *store,
+                    WorkerProto::ReadConn { .from = from });
+            });
+
+            ASSERT_EQ(got, value);
+        }
+    }
+
+    /**
+     * Golden test for `T` write
+     */
+    template<typename T>
+    void writeTest(PathView testStem, const T & value)
+    {
+        auto file = goldenMaster(testStem);
+
+        StringSink to;
+        WorkerProto::write(
+            *store,
+            WorkerProto::WriteConn { .to = to },
+            value);
+
+        if (testAccept())
+        {
+            createDirs(dirOf(file));
+            writeFile(file, to.s);
+            GTEST_SKIP() << "Updating golden master";
+        }
+        else
+        {
+            auto expected = readFile(file);
+            ASSERT_EQ(to.s, expected);
+        }
+    }
+};
+
+#define CHARACTERIZATION_TEST(NAME, STEM, VALUE)  \
+    TEST_F(WorkerProtoTest, NAME ## _read) {   \
+        readTest(STEM, VALUE);                 \
+    }                                          \
+    TEST_F(WorkerProtoTest, NAME ## _write) {  \
+        writeTest(STEM, VALUE);                \
+    }
+
+CHARACTERIZATION_TEST(
+    string,
+    "string",
+    (std::tuple<std::string, std::string, std::string, std::string, std::string> {
+        "",
+        "hi",
+        "white rabbit",
+        "大白兔",
+        "oh no \0\0\0 what was that!",
+    }))
+
+CHARACTERIZATION_TEST(
+    storePath,
+    "store-path",
+    (std::tuple<StorePath, StorePath> {
+        StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
+        StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo-bar" },
+    }))
+
+CHARACTERIZATION_TEST(
+    contentAddress,
+    "content-address",
+    (std::tuple<ContentAddress, ContentAddress, ContentAddress> {
+        ContentAddress {
+            .method = TextIngestionMethod {},
+            .hash = hashString(HashType::htSHA256, "Derive(...)"),
+        },
+        ContentAddress {
+            .method = FileIngestionMethod::Flat,
+            .hash = hashString(HashType::htSHA1, "blob blob..."),
+        },
+        ContentAddress {
+            .method = FileIngestionMethod::Recursive,
+            .hash = hashString(HashType::htSHA256, "(...)"),
+        },
+    }))
+
+CHARACTERIZATION_TEST(
+    derivedPath,
+    "derived-path",
+    (std::tuple<DerivedPath, DerivedPath> {
+        DerivedPath::Opaque {
+            .path = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
+        },
+        DerivedPath::Built {
+            .drvPath = makeConstantStorePathRef(StorePath {
+                "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
+            }),
+            .outputs = OutputsSpec::Names { "x", "y" },
+        },
+    }))
+
+}
diff --git a/unit-test-data/libstore/worker-protocol/content-address.bin b/unit-test-data/libstore/worker-protocol/content-address.bin
new file mode 100644
index 000000000..8f14bcdb3
--- /dev/null
+++ b/unit-test-data/libstore/worker-protocol/content-address.bin
diff --git a/unit-test-data/libstore/worker-protocol/derived-path.bin b/unit-test-data/libstore/worker-protocol/derived-path.bin
new file mode 100644
index 000000000..bb1a81ac6
--- /dev/null
+++ b/unit-test-data/libstore/worker-protocol/derived-path.bin
diff --git a/unit-test-data/libstore/worker-protocol/store-path.bin b/unit-test-data/libstore/worker-protocol/store-path.bin
new file mode 100644
index 000000000..3fc05f298
--- /dev/null
+++ b/unit-test-data/libstore/worker-protocol/store-path.bin
diff --git a/unit-test-data/libstore/worker-protocol/string.bin b/unit-test-data/libstore/worker-protocol/string.bin
new file mode 100644
index 000000000..aa7b5a604
--- /dev/null
+++ b/unit-test-data/libstore/worker-protocol/string.bin