FASTBuild: Generate test_prep/ targets for test build dependencies

Issue: #27879

Help/command/add_test.rst

@@ -63,7 +63,8 @@ directory the test is created in.
   * .. versionadded:: 4.4
 
       When the :variable:`CMAKE_TEST_BUILD_DEPENDS` variable is enabled,
-      the :ref:`Ninja Generators` generate a convenience build target named
+      the :ref:`Ninja Generators` and :generator:`FASTBuild` generate a
+      convenience build target named
       ``test_prep/<name>`` that depends on the test executable target. Building
       this target ensures the executable is up-to-date before the test runs.
 
@@ -79,6 +80,10 @@ directory the test is created in.
       The ``BUILD_DEPENDS`` keyword can be used to add explicit build
       dependencies.
 
+    .. versionchanged:: 4.5
+
+      :generator:`FASTBuild` gained support for ``test_prep/<name>`` targets.
+
   The command may be specified using
   :manual:`generator expressions <cmake-generator-expressions(7)>`.
 
@@ -96,9 +101,9 @@ directory the test is created in.
 
   Specify a list of targets or files that must be built before the test can
   run. Each dependency is added to the ``test_prep/<name>`` build target
-  described above when :variable:`CMAKE_TEST_BUILD_DEPENDS` is enabled
-  with the :ref:`Ninja Generators`. The test name must be a valid target name
-  in order to list build dependencies with this keyword.
+  described above when :variable:`CMAKE_TEST_BUILD_DEPENDS` is enabled with
+  the :ref:`Ninja Generators` or :generator:`FASTBuild`. The test name must be
+  a valid target name in order to list build dependencies with this keyword.
 
 ``COMMAND_EXPAND_LISTS``
   .. versionadded:: 3.16

Help/variable/CMAKE_TEST_BUILD_DEPENDS.rst

@@ -3,8 +3,13 @@ CMAKE_TEST_BUILD_DEPENDS
 
 .. versionadded:: 4.4
 
+.. versionchanged:: 4.5
+
+  :generator:`FASTBuild` gained support for ``test_prep/<name>`` targets.
+
 Enable ``test_prep/<name>`` build targets for tests added by
-:command:`add_test` when using the :ref:`Ninja Generators`.
+:command:`add_test` when using the :ref:`Ninja Generators` or
+:generator:`FASTBuild`.
 
 When this variable is set to a true value, CMake generates a
 ``test_prep/<name>`` target for each eligible test and a ``test_prep/all``

Source/cmGlobalFastbuildGenerator.cxx

@@ -32,6 +32,8 @@
 #include "cmStateSnapshot.h"
 #include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
+#include "cmTest.h"
+#include "cmTestGenerator.h"
 #include "cmValue.h"
 #include "cmVersion.h"
 #include "cmake.h"
@@ -1583,6 +1585,62 @@ void cmGlobalFastbuildGenerator::AddTargetAll()
   this->AddTarget(std::move(allAliasNode));
 }
 
+void cmGlobalFastbuildGenerator::WriteTestPrepTargets()
+{
+  if (!this->Makefiles.front()->IsOn("CMAKE_TEST_BUILD_DEPENDS")) {
+    return;
+  }
+
+  struct TestPrepTarget
+  {
+    std::string Comment;
+    std::set<FastbuildTargetDep> Dependencies;
+  };
+
+  std::map<std::string, TestPrepTarget> testPrepTargets;
+  for (auto const& localGen : this->LocalGenerators) {
+    auto const& testGenerators = localGen->GetMakefile()->GetTestGenerators();
+    for (auto const& tester : testGenerators) {
+      cmTestGenerator::BuildDependencies testDeps;
+      if (!tester->GetBuildDependencies(localGen.get(), testDeps)) {
+        continue;
+      }
+      std::string const depName =
+        cmStrCat("test_prep/", tester->GetTest()->GetName());
+      auto& testPrepTarget = testPrepTargets[depName];
+      testPrepTarget.Comment =
+        cmStrCat("Build dependencies for test ", tester->GetTest()->GetName());
+
+      for (cmGeneratorTarget* depTarget : testDeps.Targets) {
+        testPrepTarget.Dependencies.emplace(depTarget->GetName());
+      }
+      for (std::string const& depFile : testDeps.Files) {
+        testPrepTarget.Dependencies.emplace(depFile);
+      }
+    }
+  }
+
+  FastbuildAliasNode allAliasNode;
+  allAliasNode.Name = "test_prep/all";
+  allAliasNode.Hidden = false;
+  for (auto& prepEntry : testPrepTargets) {
+    FastbuildAliasNode alias;
+    alias.Name = prepEntry.first;
+    alias.Hidden = false;
+    alias.PreBuildDependencies = std::move(prepEntry.second.Dependencies);
+    if (alias.PreBuildDependencies.empty()) {
+      alias.PreBuildDependencies.emplace(FASTBUILD_NOOP_FILE_NAME);
+    }
+    this->WriteComment(prepEntry.second.Comment);
+    this->WriteAlias(alias);
+    allAliasNode.PreBuildDependencies.emplace(prepEntry.first);
+  }
+  if (!allAliasNode.PreBuildDependencies.empty()) {
+    this->WriteComment("Build dependencies for all tests");
+    this->WriteAlias(allAliasNode);
+  }
+}
+
 void cmGlobalFastbuildGenerator::AddGlobCheckExec()
 {
   // Tested in "RunCMake.file" test.
@@ -1875,6 +1933,8 @@ void cmGlobalFastbuildGenerator::WriteTargets()
     *BuildFileStream << "}\n";
   }
 
+  WriteTestPrepTargets();
+
   if (!this->GetCMakeInstance()->GetIsInTryCompile()) {
     if (!IDEProjects.empty()) {
       this->WriteIDEProjects();

Source/cmGlobalFastbuildGenerator.h

@@ -543,6 +543,7 @@ public:
   void WriteTargetClean();
 
   void AddTargetAll();
+  void WriteTestPrepTargets();
   void AddGlobCheckExec();
 
   void AddCompiler(std::string const& lang, cmMakefile* mf);

Tests/RunCMake/add_test/RunCMakeTest.cmake

@@ -71,7 +71,7 @@ function(run_testdependency_case CASE_NAME EXPECT_PRESENT)
   unset(RunCMake_TEST_NO_CLEAN)
 endfunction()
 
-if(RunCMake_GENERATOR MATCHES Ninja)
+if(RunCMake_GENERATOR MATCHES "Ninja|FASTBuild")
   block()
     run_testdependency_case(DEFAULT FALSE)
     run_testdependency_case(OFF FALSE)

Tests/RunCMake/add_test/TestDependency-check-targets.cmake

@@ -8,7 +8,8 @@ endif()
 
 file(GLOB ninja_files LIST_DIRECTORIES false
   "${RunCMake_TEST_BINARY_DIR}/*.ninja"
-  "${RunCMake_TEST_BINARY_DIR}/*.ninja.in")
+  "${RunCMake_TEST_BINARY_DIR}/*.ninja.in"
+  "${RunCMake_TEST_BINARY_DIR}/fbuild.bff")
 
 set(found FALSE)
 foreach(ninja_file IN LISTS ninja_files)