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, 370 insertions, 0 deletions

diff --git a/tests/unit/libutil/logging.cc b/tests/unit/libutil/logging.cc
new file mode 100644
index 000000000..2ffdc2e9b
--- /dev/null
+++ b/tests/unit/libutil/logging.cc
@@ -0,0 +1,370 @@
+#if 0
+
+#include "logging.hh"
+#include "nixexpr.hh"
+#include "util.hh"
+#include <fstream>
+
+#include <gtest/gtest.h>
+
+namespace nix {
+
+    /* ----------------------------------------------------------------------------
+     * logEI
+     * --------------------------------------------------------------------------*/
+
+    const char *test_file =
+        "previous line of code\n"
+        "this is the problem line of code\n"
+        "next line of code\n";
+    const char *one_liner =
+        "this is the other problem line of code";
+
+    TEST(logEI, catpuresBasicProperties) {
+
+        MakeError(TestError, Error);
+        ErrorInfo::programName = std::optional("error-unit-test");
+
+        try {
+            throw TestError("an error for testing purposes");
+        } catch (Error &e) {
+            testing::internal::CaptureStderr();
+            logger->logEI(e.info());
+            auto str = testing::internal::GetCapturedStderr();
+
+            ASSERT_STREQ(str.c_str(),"\x1B[31;1merror:\x1B[0m\x1B[34;1m --- TestError --- error-unit-test\x1B[0m\nan error for testing purposes\n");
+        }
+    }
+
+    TEST(logEI, jsonOutput) {
+        SymbolTable testTable;
+        auto problem_file = testTable.create("random.nix");
+        testing::internal::CaptureStderr();
+
+        makeJSONLogger(*logger)->logEI({
+                .name = "error name",
+                .msg = hintfmt("this hint has %1% templated %2%!!",
+                    "yellow",
+                    "values"),
+                .errPos = Pos(foFile, problem_file, 02, 13)
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "@nix {\"action\":\"msg\",\"column\":13,\"file\":\"random.nix\",\"level\":0,\"line\":2,\"msg\":\"\\u001b[31;1merror:\\u001b[0m\\u001b[34;1m --- error name --- error-unit-test\\u001b[0m\\n\\u001b[34;1mat: \\u001b[33;1m(2:13)\\u001b[34;1m in file: \\u001b[0mrandom.nix\\n\\nerror without any code lines.\\n\\nthis hint has \\u001b[33;1myellow\\u001b[0m templated \\u001b[33;1mvalues\\u001b[0m!!\",\"raw_msg\":\"this hint has \\u001b[33;1myellow\\u001b[0m templated \\u001b[33;1mvalues\\u001b[0m!!\"}\n");
+    }
+
+    TEST(logEI, appendingHintsToPreviousError) {
+
+        MakeError(TestError, Error);
+        ErrorInfo::programName = std::optional("error-unit-test");
+
+        try {
+            auto e = Error("initial error");
+            throw TestError(e.info());
+        } catch (Error &e) {
+            ErrorInfo ei = e.info();
+            ei.msg = hintfmt("%s; subsequent error message.", normaltxt(e.info().msg.str()));
+
+            testing::internal::CaptureStderr();
+            logger->logEI(ei);
+            auto str = testing::internal::GetCapturedStderr();
+
+            ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- TestError --- error-unit-test\x1B[0m\ninitial error; subsequent error message.\n");
+        }
+
+    }
+
+    TEST(logEI, picksUpSysErrorExitCode) {
+
+        MakeError(TestError, Error);
+        ErrorInfo::programName = std::optional("error-unit-test");
+
+        try {
+            auto x = readFile(-1);
+        }
+        catch (SysError &e) {
+            testing::internal::CaptureStderr();
+            logError(e.info());
+            auto str = testing::internal::GetCapturedStderr();
+
+            ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- SysError --- error-unit-test\x1B[0m\nstatting file: \x1B[33;1mBad file descriptor\x1B[0m\n");
+        }
+    }
+
+    TEST(logEI, loggingErrorOnInfoLevel) {
+        testing::internal::CaptureStderr();
+
+        logger->logEI({ .level = lvlInfo,
+                        .name = "Info name",
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[32;1minfo:\x1B[0m\x1B[34;1m --- Info name --- error-unit-test\x1B[0m\nInfo description\n");
+    }
+
+    TEST(logEI, loggingErrorOnTalkativeLevel) {
+        verbosity = lvlTalkative;
+
+        testing::internal::CaptureStderr();
+
+        logger->logEI({ .level = lvlTalkative,
+                        .name = "Talkative name",
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[32;1mtalk:\x1B[0m\x1B[34;1m --- Talkative name --- error-unit-test\x1B[0m\nTalkative description\n");
+    }
+
+    TEST(logEI, loggingErrorOnChattyLevel) {
+        verbosity = lvlChatty;
+
+        testing::internal::CaptureStderr();
+
+        logger->logEI({ .level = lvlChatty,
+                        .name = "Chatty name",
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[32;1mchat:\x1B[0m\x1B[34;1m --- Chatty name --- error-unit-test\x1B[0m\nTalkative description\n");
+    }
+
+    TEST(logEI, loggingErrorOnDebugLevel) {
+        verbosity = lvlDebug;
+
+        testing::internal::CaptureStderr();
+
+        logger->logEI({ .level = lvlDebug,
+                        .name = "Debug name",
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[33;1mdebug:\x1B[0m\x1B[34;1m --- Debug name --- error-unit-test\x1B[0m\nDebug description\n");
+    }
+
+    TEST(logEI, loggingErrorOnVomitLevel) {
+        verbosity = lvlVomit;
+
+        testing::internal::CaptureStderr();
+
+        logger->logEI({ .level = lvlVomit,
+                        .name = "Vomit name",
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[32;1mvomit:\x1B[0m\x1B[34;1m --- Vomit name --- error-unit-test\x1B[0m\nVomit description\n");
+    }
+
+    /* ----------------------------------------------------------------------------
+     * logError
+     * --------------------------------------------------------------------------*/
+
+    TEST(logError, logErrorWithoutHintOrCode) {
+        testing::internal::CaptureStderr();
+
+        logError({
+                .name = "name",
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- name --- error-unit-test\x1B[0m\nerror description\n");
+    }
+
+    TEST(logError, logErrorWithPreviousAndNextLinesOfCode) {
+        SymbolTable testTable;
+        auto problem_file = testTable.create(test_file);
+
+        testing::internal::CaptureStderr();
+
+        logError({
+                .name = "error name",
+                .msg = hintfmt("this hint has %1% templated %2%!!",
+                    "yellow",
+                    "values"),
+                .errPos = Pos(foString, problem_file, 02, 13),
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- error name --- error-unit-test\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(2:13)\x1B[34;1m from string\x1B[0m\n\nerror with code lines\n\n     1| previous line of code\n     2| this is the problem line of code\n      |             \x1B[31;1m^\x1B[0m\n     3| next line of code\n\nthis hint has \x1B[33;1myellow\x1B[0m templated \x1B[33;1mvalues\x1B[0m!!\n");
+    }
+
+    TEST(logError, logErrorWithInvalidFile) {
+        SymbolTable testTable;
+        auto problem_file = testTable.create("invalid filename");
+        testing::internal::CaptureStderr();
+
+        logError({
+                .name = "error name",
+                .msg = hintfmt("this hint has %1% templated %2%!!",
+                    "yellow",
+                    "values"),
+                .errPos = Pos(foFile, problem_file, 02, 13)
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- error name --- error-unit-test\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(2:13)\x1B[34;1m in file: \x1B[0minvalid filename\n\nerror without any code lines.\n\nthis hint has \x1B[33;1myellow\x1B[0m templated \x1B[33;1mvalues\x1B[0m!!\n");
+    }
+
+    TEST(logError, logErrorWithOnlyHintAndName) {
+        testing::internal::CaptureStderr();
+
+        logError({
+                .name = "error name",
+                .msg = hintfmt("hint %1%", "only"),
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- error name --- error-unit-test\x1B[0m\nhint \x1B[33;1monly\x1B[0m\n");
+
+    }
+
+    /* ----------------------------------------------------------------------------
+     * logWarning
+     * --------------------------------------------------------------------------*/
+
+    TEST(logWarning, logWarningWithNameDescriptionAndHint) {
+        testing::internal::CaptureStderr();
+
+        logWarning({
+                .name = "name",
+                .msg = hintfmt("there was a %1%", "warning"),
+            });
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[33;1mwarning:\x1B[0m\x1B[34;1m --- name --- error-unit-test\x1B[0m\nwarning description\n\nthere was a \x1B[33;1mwarning\x1B[0m\n");
+    }
+
+    TEST(logWarning, logWarningWithFileLineNumAndCode) {
+
+        SymbolTable testTable;
+        auto problem_file = testTable.create(test_file);
+
+        testing::internal::CaptureStderr();
+
+        logWarning({
+                .name = "warning name",
+                .msg = hintfmt("this hint has %1% templated %2%!!",
+                    "yellow",
+                    "values"),
+                .errPos = Pos(foStdin, problem_file, 2, 13),
+            });
+
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[33;1mwarning:\x1B[0m\x1B[34;1m --- warning name --- error-unit-test\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(2:13)\x1B[34;1m from stdin\x1B[0m\n\nwarning description\n\n     1| previous line of code\n     2| this is the problem line of code\n      |             \x1B[31;1m^\x1B[0m\n     3| next line of code\n\nthis hint has \x1B[33;1myellow\x1B[0m templated \x1B[33;1mvalues\x1B[0m!!\n");
+    }
+
+    /* ----------------------------------------------------------------------------
+     * traces
+     * --------------------------------------------------------------------------*/
+
+    TEST(addTrace, showTracesWithShowTrace) {
+        SymbolTable testTable;
+        auto problem_file = testTable.create(test_file);
+        auto oneliner_file = testTable.create(one_liner);
+        auto invalidfilename = testTable.create("invalid filename");
+
+        auto e = AssertionError(ErrorInfo {
+                .name = "wat",
+                .msg = hintfmt("it has been %1% days since our last error", "zero"),
+                .errPos = Pos(foString, problem_file, 2, 13),
+            });
+
+        e.addTrace(Pos(foStdin, oneliner_file, 1, 19), "while trying to compute %1%", 42);
+        e.addTrace(std::nullopt, "while doing something without a %1%", "pos");
+        e.addTrace(Pos(foFile, invalidfilename, 100, 1), "missing %s", "nix file");
+
+        testing::internal::CaptureStderr();
+
+        loggerSettings.showTrace.assign(true);
+
+        logError(e.info());
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- AssertionError --- error-unit-test\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(2:13)\x1B[34;1m from string\x1B[0m\n\nshow-traces\n\n     1| previous line of code\n     2| this is the problem line of code\n      |             \x1B[31;1m^\x1B[0m\n     3| next line of code\n\nit has been \x1B[33;1mzero\x1B[0m days since our last error\n\x1B[34;1m---- show-trace ----\x1B[0m\n\x1B[34;1mtrace: \x1B[0mwhile trying to compute \x1B[33;1m42\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(1:19)\x1B[34;1m from stdin\x1B[0m\n\n     1| this is the other problem line of code\n      |                   \x1B[31;1m^\x1B[0m\n\n\x1B[34;1mtrace: \x1B[0mwhile doing something without a \x1B[33;1mpos\x1B[0m\n\x1B[34;1mtrace: \x1B[0mmissing \x1B[33;1mnix file\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(100:1)\x1B[34;1m in file: \x1B[0minvalid filename\n");
+    }
+
+    TEST(addTrace, hideTracesWithoutShowTrace) {
+        SymbolTable testTable;
+        auto problem_file = testTable.create(test_file);
+        auto oneliner_file = testTable.create(one_liner);
+        auto invalidfilename = testTable.create("invalid filename");
+
+        auto e = AssertionError(ErrorInfo {
+                .name = "wat",
+                .msg = hintfmt("it has been %1% days since our last error", "zero"),
+                .errPos = Pos(foString, problem_file, 2, 13),
+            });
+
+        e.addTrace(Pos(foStdin, oneliner_file, 1, 19), "while trying to compute %1%", 42);
+        e.addTrace(std::nullopt, "while doing something without a %1%", "pos");
+        e.addTrace(Pos(foFile, invalidfilename, 100, 1), "missing %s", "nix file");
+
+        testing::internal::CaptureStderr();
+
+        loggerSettings.showTrace.assign(false);
+
+        logError(e.info());
+
+        auto str = testing::internal::GetCapturedStderr();
+        ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- AssertionError --- error-unit-test\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(2:13)\x1B[34;1m from string\x1B[0m\n\nhide traces\n\n     1| previous line of code\n     2| this is the problem line of code\n      |             \x1B[31;1m^\x1B[0m\n     3| next line of code\n\nit has been \x1B[33;1mzero\x1B[0m days since our last error\n");
+    }
+
+
+    /* ----------------------------------------------------------------------------
+     * hintfmt
+     * --------------------------------------------------------------------------*/
+
+    TEST(hintfmt, percentStringWithoutArgs) {
+
+        const char *teststr = "this is 100%s correct!";
+
+        ASSERT_STREQ(
+            hintfmt(teststr).str().c_str(),
+            teststr);
+
+    }
+
+    TEST(hintfmt, fmtToHintfmt) {
+
+        ASSERT_STREQ(
+            hintfmt(fmt("the color of this this text is %1%", "not yellow")).str().c_str(),
+            "the color of this this text is not yellow");
+
+    }
+
+    TEST(hintfmt, tooFewArguments) {
+
+        ASSERT_STREQ(
+            hintfmt("only one arg %1% %2%", "fulfilled").str().c_str(),
+            "only one arg " ANSI_WARNING "fulfilled" ANSI_NORMAL " ");
+
+    }
+
+    TEST(hintfmt, tooManyArguments) {
+
+        ASSERT_STREQ(
+            hintfmt("what about this %1% %2%", "%3%", "one", "two").str().c_str(),
+            "what about this " ANSI_WARNING "%3%" ANSI_NORMAL " " ANSI_YELLOW "one" ANSI_NORMAL);
+
+    }
+
+    /* ----------------------------------------------------------------------------
+     * ErrPos
+     * --------------------------------------------------------------------------*/
+
+    TEST(errpos, invalidPos) {
+
+      // contains an invalid symbol, which we should not dereference!
+      Pos invalid;
+
+      // constructing without access violation.
+      ErrPos ep(invalid);
+
+      // assignment without access violation.
+      ep = invalid;
+
+    }
+
+}
+
+#endif