Move tests to separate directories, and document

Today, with the tests inside a `tests` intermingled with the
corresponding library's source code, we have a few problems:

- We have to be careful that wildcards don't end up with tests being
  built as part of Nix proper, or test headers being installed as part
  of Nix proper.

- Tests in libraries but not executables is not right:

  - It means each executable runs the previous unit tests again, because
    it needs the libraries.

  - It doesn't work right on Windows, which doesn't want you to load a
    DLL just for the side global variable . It could be made to work
    with the dlopen equivalent, but that's gross!

This reorg solves these problems.

There is a remaining problem which is that sibbling headers (like
`hash.hh` the test header vs `hash.hh` the main `libnixutil` header) end
up shadowing each other. This PR doesn't solve that. That is left as
future work for a future PR.

Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>

(cherry picked from commit 91b6833686a6a6d9eac7f3f66393ec89ef1d3b57)
(cherry picked from commit a61e42adb528b3d40ce43e07c79368d779a8b624)

1 files changed, 369 insertions, 0 deletions

diff --git a/tests/unit/libstore/derivation.cc b/tests/unit/libstore/derivation.cc
new file mode 100644
index 000000000..c360c9707
--- /dev/null
+++ b/tests/unit/libstore/derivation.cc
@@ -0,0 +1,369 @@
+#include <nlohmann/json.hpp>
+#include <gtest/gtest.h>
+
+#include "experimental-features.hh"
+#include "derivations.hh"
+
+#include "tests/libstore.hh"
+
+namespace nix {
+
+class DerivationTest : public LibStoreTest
+{
+public:
+    /**
+     * We set these in tests rather than the regular globals so we don't have
+     * to worry about race conditions if the tests run concurrently.
+     */
+    ExperimentalFeatureSettings mockXpSettings;
+};
+
+class CaDerivationTest : public DerivationTest
+{
+    void SetUp() override
+    {
+        mockXpSettings.set("experimental-features", "ca-derivations");
+    }
+};
+
+class DynDerivationTest : public DerivationTest
+{
+    void SetUp() override
+    {
+        mockXpSettings.set("experimental-features", "dynamic-derivations ca-derivations");
+    }
+};
+
+class ImpureDerivationTest : public DerivationTest
+{
+    void SetUp() override
+    {
+        mockXpSettings.set("experimental-features", "impure-derivations");
+    }
+};
+
+TEST_F(DerivationTest, BadATerm_version) {
+    ASSERT_THROW(
+        parseDerivation(
+            *store,
+            R"(DrvWithVersion("invalid-version",[],[("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv",["cat","dog"])],["/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"],"wasm-sel4","foo",["bar","baz"],[("BIG_BAD","WOLF")]))",
+            "whatever",
+            mockXpSettings),
+        FormatError);
+}
+
+TEST_F(DynDerivationTest, BadATerm_oldVersionDynDeps) {
+    ASSERT_THROW(
+        parseDerivation(
+            *store,
+            R"(Derive([],[("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv",(["cat","dog"],[("cat",["kitten"]),("goose",["gosling"])]))],["/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"],"wasm-sel4","foo",["bar","baz"],[("BIG_BAD","WOLF")]))",
+            "dyn-dep-derivation",
+            mockXpSettings),
+        FormatError);
+}
+
+#define TEST_JSON(FIXTURE, NAME, STR, VAL, DRV_NAME, OUTPUT_NAME) \
+    TEST_F(FIXTURE, DerivationOutput_ ## NAME ## _to_json) {    \
+        using nlohmann::literals::operator "" _json;           \
+        ASSERT_EQ(                                             \
+            STR ## _json,                                      \
+            (DerivationOutput { VAL }).toJSON(                 \
+                *store,                                        \
+                DRV_NAME,                                      \
+                OUTPUT_NAME));                                 \
+    }                                                          \
+                                                               \
+    TEST_F(FIXTURE, DerivationOutput_ ## NAME ## _from_json) {  \
+        using nlohmann::literals::operator "" _json;           \
+        ASSERT_EQ(                                             \
+            DerivationOutput { VAL },                          \
+            DerivationOutput::fromJSON(                        \
+                *store,                                        \
+                DRV_NAME,                                      \
+                OUTPUT_NAME,                                   \
+                STR ## _json,                                  \
+                mockXpSettings));                              \
+    }
+
+TEST_JSON(DerivationTest, inputAddressed,
+    R"({
+        "path": "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-drv-name-output-name"
+    })",
+    (DerivationOutput::InputAddressed {
+        .path = store->parseStorePath("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-drv-name-output-name"),
+    }),
+    "drv-name", "output-name")
+
+TEST_JSON(DerivationTest, caFixedFlat,
+    R"({
+        "hashAlgo": "sha256",
+        "hash": "894517c9163c896ec31a2adbd33c0681fd5f45b2c0ef08a64c92a03fb97f390f",
+        "path": "/nix/store/rhcg9h16sqvlbpsa6dqm57sbr2al6nzg-drv-name-output-name"
+    })",
+    (DerivationOutput::CAFixed {
+        .ca = {
+            .method = FileIngestionMethod::Flat,
+            .hash = Hash::parseAnyPrefixed("sha256-iUUXyRY8iW7DGirb0zwGgf1fRbLA7wimTJKgP7l/OQ8="),
+        },
+    }),
+    "drv-name", "output-name")
+
+TEST_JSON(DerivationTest, caFixedNAR,
+    R"({
+        "hashAlgo": "r:sha256",
+        "hash": "894517c9163c896ec31a2adbd33c0681fd5f45b2c0ef08a64c92a03fb97f390f",
+        "path": "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-drv-name-output-name"
+    })",
+    (DerivationOutput::CAFixed {
+        .ca = {
+            .method = FileIngestionMethod::Recursive,
+            .hash = Hash::parseAnyPrefixed("sha256-iUUXyRY8iW7DGirb0zwGgf1fRbLA7wimTJKgP7l/OQ8="),
+        },
+    }),
+    "drv-name", "output-name")
+
+TEST_JSON(DynDerivationTest, caFixedText,
+    R"({
+        "hashAlgo": "text:sha256",
+        "hash": "894517c9163c896ec31a2adbd33c0681fd5f45b2c0ef08a64c92a03fb97f390f",
+        "path": "/nix/store/6s1zwabh956jvhv4w9xcdb5jiyanyxg1-drv-name-output-name"
+    })",
+    (DerivationOutput::CAFixed {
+        .ca = {
+            .hash = Hash::parseAnyPrefixed("sha256-iUUXyRY8iW7DGirb0zwGgf1fRbLA7wimTJKgP7l/OQ8="),
+        },
+    }),
+    "drv-name", "output-name")
+
+TEST_JSON(CaDerivationTest, caFloating,
+    R"({
+        "hashAlgo": "r:sha256"
+    })",
+    (DerivationOutput::CAFloating {
+        .method = FileIngestionMethod::Recursive,
+        .hashType = htSHA256,
+    }),
+    "drv-name", "output-name")
+
+TEST_JSON(DerivationTest, deferred,
+    R"({ })",
+    DerivationOutput::Deferred { },
+    "drv-name", "output-name")
+
+TEST_JSON(ImpureDerivationTest, impure,
+    R"({
+        "hashAlgo": "r:sha256",
+        "impure": true
+    })",
+    (DerivationOutput::Impure {
+        .method = FileIngestionMethod::Recursive,
+        .hashType = htSHA256,
+    }),
+    "drv-name", "output-name")
+
+#undef TEST_JSON
+
+#define TEST_JSON(FIXTURE, NAME, STR, VAL)                       \
+    TEST_F(FIXTURE, Derivation_ ## NAME ## _to_json) {           \
+        using nlohmann::literals::operator "" _json;             \
+        ASSERT_EQ(                                               \
+            STR ## _json,                                        \
+            (VAL).toJSON(*store));                               \
+    }                                                            \
+                                                                 \
+    TEST_F(FIXTURE, Derivation_ ## NAME ## _from_json) {         \
+        using nlohmann::literals::operator "" _json;             \
+        ASSERT_EQ(                                               \
+            (VAL),                                               \
+            Derivation::fromJSON(                                \
+                *store,                                          \
+                STR ## _json,                                    \
+                mockXpSettings));                                \
+    }
+
+#define TEST_ATERM(FIXTURE, NAME, STR, VAL, DRV_NAME)            \
+    TEST_F(FIXTURE, Derivation_ ## NAME ## _to_aterm) {          \
+        ASSERT_EQ(                                               \
+            STR,                                                 \
+            (VAL).unparse(*store, false));                       \
+    }                                                            \
+                                                                 \
+    TEST_F(FIXTURE, Derivation_ ## NAME ## _from_aterm) {        \
+        auto parsed = parseDerivation(                           \
+            *store,                                              \
+            STR,                                                 \
+            DRV_NAME,                                            \
+            mockXpSettings);                                     \
+        ASSERT_EQ(                                               \
+            (VAL).toJSON(*store),                                \
+            parsed.toJSON(*store));                              \
+        ASSERT_EQ(                                               \
+            (VAL),                                               \
+            parsed);                                             \
+    }
+
+Derivation makeSimpleDrv(const Store & store) {
+    Derivation drv;
+    drv.name = "simple-derivation";
+    drv.inputSrcs = {
+        store.parseStorePath("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"),
+    };
+    drv.inputDrvs = {
+        .map = {
+            {
+                store.parseStorePath("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv"),
+                {
+                    .value = {
+                        "cat",
+                        "dog",
+                    },
+                },
+            },
+        },
+    };
+    drv.platform = "wasm-sel4";
+    drv.builder = "foo";
+    drv.args = {
+        "bar",
+        "baz",
+    };
+    drv.env = {
+        {
+            "BIG_BAD",
+            "WOLF",
+        },
+    };
+    return drv;
+}
+
+TEST_JSON(DerivationTest, simple,
+    R"({
+      "name": "simple-derivation",
+      "inputSrcs": [
+        "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"
+      ],
+      "inputDrvs": {
+        "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv": {
+          "dynamicOutputs": {},
+          "outputs": [
+            "cat",
+            "dog"
+          ]
+        }
+      },
+      "system": "wasm-sel4",
+      "builder": "foo",
+      "args": [
+        "bar",
+        "baz"
+      ],
+      "env": {
+        "BIG_BAD": "WOLF"
+      },
+      "outputs": {}
+    })",
+    makeSimpleDrv(*store))
+
+TEST_ATERM(DerivationTest, simple,
+    R"(Derive([],[("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv",["cat","dog"])],["/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"],"wasm-sel4","foo",["bar","baz"],[("BIG_BAD","WOLF")]))",
+    makeSimpleDrv(*store),
+    "simple-derivation")
+
+Derivation makeDynDepDerivation(const Store & store) {
+    Derivation drv;
+    drv.name = "dyn-dep-derivation";
+    drv.inputSrcs = {
+        store.parseStorePath("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"),
+    };
+    drv.inputDrvs = {
+        .map = {
+            {
+                store.parseStorePath("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv"),
+                DerivedPathMap<StringSet>::ChildNode {
+                    .value = {
+                        "cat",
+                        "dog",
+                    },
+                    .childMap = {
+                        {
+                            "cat",
+                            DerivedPathMap<StringSet>::ChildNode {
+                                .value = {
+                                    "kitten",
+                                },
+                            },
+                        },
+                        {
+                            "goose",
+                            DerivedPathMap<StringSet>::ChildNode {
+                                .value = {
+                                    "gosling",
+                                },
+                            },
+                        },
+                    },
+                },
+            },
+        },
+    };
+    drv.platform = "wasm-sel4";
+    drv.builder = "foo";
+    drv.args = {
+        "bar",
+        "baz",
+    };
+    drv.env = {
+        {
+            "BIG_BAD",
+            "WOLF",
+        },
+    };
+    return drv;
+}
+
+TEST_JSON(DynDerivationTest, dynDerivationDeps,
+    R"({
+      "name": "dyn-dep-derivation",
+      "inputSrcs": [
+        "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"
+      ],
+      "inputDrvs": {
+        "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv": {
+          "dynamicOutputs": {
+            "cat": {
+              "dynamicOutputs": {},
+              "outputs": ["kitten"]
+            },
+            "goose": {
+              "dynamicOutputs": {},
+              "outputs": ["gosling"]
+            }
+          },
+          "outputs": [
+            "cat",
+            "dog"
+          ]
+        }
+      },
+      "system": "wasm-sel4",
+      "builder": "foo",
+      "args": [
+        "bar",
+        "baz"
+      ],
+      "env": {
+        "BIG_BAD": "WOLF"
+      },
+      "outputs": {}
+    })",
+    makeDynDepDerivation(*store))
+
+TEST_ATERM(DynDerivationTest, dynDerivationDeps,
+    R"(DrvWithVersion("xp-dyn-drv",[],[("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv",(["cat","dog"],[("cat",["kitten"]),("goose",["gosling"])]))],["/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"],"wasm-sel4","foo",["bar","baz"],[("BIG_BAD","WOLF")]))",
+    makeDynDepDerivation(*store),
+    "dyn-dep-derivation")
+
+#undef TEST_JSON
+#undef TEST_ATERM
+
+}