Add statement/condition coverage measurement for the test suite.

We're using gcov+lcov, since these tools appear to be the only
usable ones that use the SC/CC metric; and measuring just the line
coverage would be practically criminal negligence.

gcov only works with GCC and Clang, and MSVC's own coverage
measurement tools are not up to the task; so MSVC is out of luck.

.travis/build-debian.sh

@@ -4,5 +4,6 @@ if echo $TRAVIS_TAG | grep ^v; then BUILD_TYPE=RelWithDebInfo; else BUILD_TYPE=D
 
 mkdir build
 cd build
-cmake -DCMAKE_C_COMPILER=gcc-5 -DCMAKE_CXX_COMPILER=g++-5 -DCMAKE_BUILD_TYPE=$BUILD_TYPE ..
+cmake -DCMAKE_C_COMPILER=gcc-5 -DCMAKE_CXX_COMPILER=g++-5 \
+  -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DENABLE_COVERAGE=ON ..
 make VERBOSE=1

.travis/install-debian.sh

@@ -5,4 +5,4 @@ sudo apt-get update -qq
 sudo apt-get install -q -y \
   cmake cmake-data libpng12-dev zlib1g-dev libjson0-dev libfontconfig1-dev \
   libgtkmm-2.4-dev libpangomm-1.4-dev libcairo2-dev libgl1-mesa-dev libglu-dev \
-  libfreetype6-dev dpkg-dev gcc-5 g++-5
+  libfreetype6-dev dpkg-dev gcc-5 g++-5 lcov

CMakeLists.txt

@@ -27,7 +27,10 @@ set(solvespace_VERSION_MAJOR 3)
 set(solvespace_VERSION_MINOR 0)
 string(SUBSTRING "${GIT_COMMIT_HASH}" 0 8 solvespace_GIT_HASH)
 
-set(ENABLE_TESTS ON CACHE BOOL "Whether the test suite will be built and run")
+set(ENABLE_TESTS    ON  CACHE BOOL
+    "Whether the test suite will be built and run")
+set(ENABLE_COVERAGE OFF CACHE BOOL
+    "Whether code coverage information will be collected")
 
 if(NOT WIN32 AND NOT APPLE)
     set(GUI gtk2 CACHE STRING "GUI toolkit to use (one of: gtk2 gtk3)")
@@ -56,7 +59,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Linux" OR CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
 endif()
 
 if(SANITIZE)
-    if(NOT (CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_ID STREQUAL "Clang"))
+    if(NOT (CMAKE_C_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
         message(ERROR "Sanitizers are only available in Clang/Clang++")
     endif()
     set(SANITIZE_FLAGS  "-O1 -fno-omit-frame-pointer -fno-optimize-sibling-calls")
@@ -162,6 +165,14 @@ else() # Linux and compatible systems
     endif()
 endif()
 
+if(ENABLE_COVERAGE)
+    find_program(LCOV lcov)
+    find_program(GENHTML genhtml)
+    if(NOT LCOV OR NOT GENHTML)
+        message(FATAL_ERROR "lcov is required for producing coverage reports")
+    endif()
+endif()
+
 # solvespace-only compiler flags
 
 if(WIN32)
@@ -193,9 +204,9 @@ if(MSVC)
     set(WARNING_FLAGS   "${WARNING_FLAGS} /we4062")
 endif()
 
-if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     set(WARNING_FLAGS   "-Wall -Wextra -Wno-unused-parameter")
-    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+    if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
         set(WARNING_FLAGS "${WARNING_FLAGS} -Wfloat-conversion")
     endif()
     # We rely on these -Werror flags.
@@ -209,6 +220,22 @@ if(WIN32)
     set(CMAKE_RC_FLAGS  "${CMAKE_RC_FLAGS} -l0")
 endif()
 
+if(ENABLE_COVERAGE)
+    if(NOT (CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR
+            CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
+        message(FATAL_ERROR "Code coverage is only available on GCC and Clang")
+    endif()
+
+    if(NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
+        message(FATAL_ERROR "Code coverage produces reliable results only on Debug builds")
+    endif()
+
+    # With -fexceptions, every call becomes a branch. While technically accurate,
+    # this is not useful for us.
+    set(COVERAGE_FLAGS -fno-exceptions --coverage)
+    set(COVERAGE_LIBRARY --coverage)
+endif()
+
 # components
 
 add_subdirectory(res)

src/CMakeLists.txt

@@ -184,6 +184,9 @@ target_link_libraries(solvespace_cad
     ${FREETYPE_LIBRARY}
     ${Backtrace_LIBRARIES})
 
+target_compile_options(solvespace_cad
+    PRIVATE ${COVERAGE_FLAGS})
+
 # solvespace gui executable
 
 add_executable(solvespace WIN32 MACOSX_BUNDLE
@@ -197,7 +200,8 @@ add_dependencies(solvespace
 target_link_libraries(solvespace
     solvespace_cad
     ${OPENGL_LIBRARIES}
-    ${platform_LIBRARIES})
+    ${platform_LIBRARIES}
+    ${COVERAGE_LIBRARY})
 
 if(WIN32 AND NOT MINGW)
     set_target_properties(solvespace PROPERTIES
@@ -256,3 +260,6 @@ target_include_directories(solvespace_headless
 target_link_libraries(solvespace_headless
     solvespace_cad
     ${CAIRO_LIBRARIES})
+
+target_compile_options(solvespace_headless
+    PRIVATE ${COVERAGE_FLAGS})

src/solvespace.h

@@ -14,6 +14,7 @@
 #include <stdio.h>
 #include <stddef.h>
 #include <stdarg.h>
+#include <setjmp.h>
 #include <math.h>
 #include <setjmp.h>
 #include <limits.h>

test/CMakeLists.txt

@@ -1,3 +1,5 @@
+# test suite
+
 include_directories(
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_BINARY_DIR})
@@ -10,9 +12,43 @@ add_executable(solvespace_testsuite
     ${testsuite_SOURCES})
 
 target_link_libraries(solvespace_testsuite
-    solvespace_headless)
+    solvespace_headless
+    ${COVERAGE_LIBRARY})
 
 add_custom_target(solvespace-test ALL
     COMMAND $<TARGET_FILE:solvespace_testsuite>
     COMMENT "Testing SolveSpace"
     VERBATIM)
+
+# coverage reports
+
+if(ENABLE_COVERAGE)
+    set(LCOV_FLAGS   -q --rc lcov_branch_coverage=1 --rc lcov_excl_line=ssassert)
+    set(LCOV_COLLECT -c -b ${CMAKE_SOURCE_DIR}/src -d ${CMAKE_BINARY_DIR}/src --no-external)
+
+    add_custom_command(
+        OUTPUT  ${CMAKE_CURRENT_BINARY_DIR}/coverage_base.info
+        COMMAND ${LCOV} ${LCOV_FLAGS} ${LCOV_COLLECT}
+            -o ${CMAKE_BINARY_DIR}/coverage_base.info -i
+        DEPENDS solvespace_testsuite
+        COMMENT "Importing baseline coverage data"
+        VERBATIM)
+
+    add_custom_target(solvespace-coverage ALL
+        COMMAND ${LCOV} ${LCOV_FLAGS} ${LCOV_COLLECT}
+            -o ${CMAKE_BINARY_DIR}/coverage_test.info
+        COMMAND ${LCOV} ${LCOV_FLAGS}
+            -o ${CMAKE_BINARY_DIR}/coverage_full.info
+            -a ${CMAKE_BINARY_DIR}/coverage_base.info
+            -a ${CMAKE_BINARY_DIR}/coverage_test.info
+        COMMAND ${LCOV} ${LCOV_FLAGS} --summary
+            ${CMAKE_BINARY_DIR}/coverage_full.info
+        COMMAND ${GENHTML} -q --branch-coverage --demangle-cpp --legend
+            ${CMAKE_BINARY_DIR}/coverage_full.info
+            -o ${CMAKE_BINARY_DIR}/coverage/
+            -t "SolveSpace testbench"
+        DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/coverage_base.info
+        DEPENDS solvespace-test
+        COMMENT "Generating coverage report"
+        VERBATIM)
+endif()