diff --git a/unittest/Makefile.am b/unittest/Makefile.am
index 5bb67f354a..4bea942cdd 100644
--- a/unittest/Makefile.am
+++ b/unittest/Makefile.am
@@ -26,6 +26,7 @@ AM_CPPFLAGS += -I$(top_srcdir)/src/training
 endif
 AM_CPPFLAGS += -I$(top_srcdir)/src/viewer
 AM_CPPFLAGS += -I$(top_srcdir)/src/wordrec
+AM_CPPFLAGS += -I$(top_srcdir)/abseil
 
 # Build googletest:
 check_LTLIBRARIES = libgtest.la libgtest_main.la libgmock.la libgmock_main.la
@@ -34,6 +35,22 @@ libgtest_la_CPPFLAGS = -I$(top_srcdir)/googletest/googletest/include -I$(top_src
 libgtest_main_la_SOURCES = ../googletest/googletest/src/gtest_main.cc
 ## libgtest_main_la_LIBADD = libgtest.la
 
+# Build Abseil (needed for some unit tests).
+check_LTLIBRARIES += libabseil.la
+libabseil_la_SOURCES =
+libabseil_la_SOURCES += ../abseil/absl/base/internal/cycleclock.cc
+libabseil_la_SOURCES += ../abseil/absl/base/internal/raw_logging.cc
+libabseil_la_SOURCES += ../abseil/absl/base/internal/spinlock.cc
+libabseil_la_SOURCES += ../abseil/absl/base/internal/spinlock_wait.cc
+libabseil_la_SOURCES += ../abseil/absl/base/internal/sysinfo.cc
+libabseil_la_SOURCES += ../abseil/absl/base/internal/throw_delegate.cc
+libabseil_la_SOURCES += ../abseil/absl/base/internal/unscaledcycleclock.cc
+libabseil_la_SOURCES += ../abseil/absl/numeric/int128.cc
+libabseil_la_SOURCES += ../abseil/absl/strings/ascii.cc
+libabseil_la_SOURCES += ../abseil/absl/strings/str_cat.cc
+libabseil_la_SOURCES += ../abseil/absl/time/clock.cc
+libabseil_la_SOURCES += ../abseil/absl/time/duration.cc
+
 GMOCK_INCLUDES = -I$(top_srcdir)/googletest/googlemock/include \
                  -I$(top_srcdir)/googletest/googlemock \
                  -I$(top_srcdir)/googletest/googletest/include \
@@ -47,6 +64,7 @@ libgmock_main_la_CPPFLAGS = $(GMOCK_INCLUDES) \
                             -pthread
 
 # Build unittests
+ABSEIL_LIBS = libabseil.la
 GTEST_LIBS =  libgtest.la libgtest_main.la
 GMOCK_LIBS =  libgmock.la libgmock_main.la
 TESS_LIBS = $(top_builddir)/src/api/libtesseract.la
@@ -59,6 +77,7 @@ AM_CPPFLAGS +=   -isystem $(top_srcdir)/googletest/googletest/include \
 check_PROGRAMS = \
   apiexample_test \
   applybox_test \
+  baseapi_test \
   bitvector_test \
   cleanapi_test \
   colpartition_test \
@@ -97,6 +116,9 @@ apiexample_test_LDADD = $(GTEST_LIBS) $(TESS_LIBS) $(LEPTONICA_LIBS)
 applybox_test_SOURCES = applybox_test.cc
 applybox_test_LDADD = $(GTEST_LIBS) $(TESS_LIBS) $(LEPTONICA_LIBS)
 
+baseapi_test_SOURCES = baseapi_test.cc
+baseapi_test_LDADD = $(ABSEIL_LIBS) $(GTEST_LIBS) $(TESS_LIBS)
+
 bitvector_test_SOURCES = bitvector_test.cc
 bitvector_test_LDADD = $(GTEST_LIBS) $(TESS_LIBS)
 
diff --git a/unittest/baseapi_test.cc b/unittest/baseapi_test.cc
index 41c7de7ddb..b7a1afeb7f 100644
--- a/unittest/baseapi_test.cc
+++ b/unittest/baseapi_test.cc
@@ -1,20 +1,40 @@
+// (C) Copyright 2017, Google Inc.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 
-#include "tesseract/api/baseapi.h"
 #include <memory>
 #include <string>
 #include <vector>
-#include "leptonica/include/allheaders.h"
-#include "tesseract/ccstruct/pageres.h"
+
+#include "absl/strings/ascii.h"
+#include "absl/strings/str_cat.h"
+#include "allheaders.h"
+
+#include "include_gunit.h"
+#include "gmock/gmock-matchers.h"
+
+#include "baseapi.h"
+#include "cycletimer.h" // for CycleTimer
+#include "log.h"        // for LOG
+#include "ocrblock.h"   // for class BLOCK
+#include "pageres.h"
 
 namespace {
 
 using ::testing::ContainsRegex;
 using ::testing::HasSubstr;
 
-const char* langs[] = {"eng", "vie", "hin", "ara", nullptr};
-const char* image_files[] = {"HelloGoogle.tif", "viet.tif", "raaj.tif",
+static const char* langs[] = {"eng", "vie", "hin", "ara", nullptr};
+static const char* image_files[] = {"HelloGoogle.tif", "viet.tif", "raaj.tif",
                              "arabic.tif", nullptr};
-const char* gt_text[] = {"Hello Google", "\x74\x69\xe1\xba\xbf\x6e\x67",
+static const char* gt_text[] = {"Hello Google", "\x74\x69\xe1\xba\xbf\x6e\x67",
                          "\xe0\xa4\xb0\xe0\xa4\xbe\xe0\xa4\x9c",
                          "\xd8\xa7\xd9\x84\xd8\xb9\xd8\xb1\xd8\xa8\xd9\x8a",
                          nullptr};
@@ -23,10 +43,10 @@ class FriendlyTessBaseAPI : public tesseract::TessBaseAPI {
   FRIEND_TEST(TesseractTest, LSTMGeometryTest);
 };
 
-string GetCleanedTextResult(tesseract::TessBaseAPI* tess, Pix* pix) {
+std::string GetCleanedTextResult(tesseract::TessBaseAPI* tess, Pix* pix) {
   tess->SetImage(pix);
   char* result = tess->GetUTF8Text();
-  string ocr_result = result;
+  std::string ocr_result = result;
   delete[] result;
   absl::StripAsciiWhitespace(&ocr_result);
   return ocr_result;
@@ -35,11 +55,11 @@ string GetCleanedTextResult(tesseract::TessBaseAPI* tess, Pix* pix) {
 // The fixture for testing Tesseract.
 class TesseractTest : public testing::Test {
  protected:
-  string TestDataNameToPath(const string& name) {
-    return file::JoinPath(FLAGS_test_srcdir, "testdata/" + name);
+  static std::string TestDataNameToPath(const std::string& name) {
+    return file::JoinPath(TESTING_DIR, name);
   }
-  string TessdataPath() {
-    return file::JoinPath(FLAGS_test_srcdir, "tessdata");
+  static std::string TessdataPath() {
+    return TESSDATA_DIR;
   }
 };
 
@@ -54,8 +74,8 @@ TEST_F(TesseractTest, ArraySizeTest) {
 // Tests that Tesseract gets exactly the right answer on phototest.
 TEST_F(TesseractTest, BasicTesseractTest) {
   tesseract::TessBaseAPI api;
-  string truth_text;
-  string ocr_text;
+  std::string truth_text;
+  std::string ocr_text;
   api.Init(TessdataPath().c_str(), "eng", tesseract::OEM_TESSERACT_ONLY);
   Pix* src_pix = pixRead(TestDataNameToPath("phototest.tif").c_str());
   CHECK(src_pix);
@@ -74,6 +94,7 @@ TEST_F(TesseractTest, IteratesParagraphsEvenIfNotDetected) {
   api.Init(TessdataPath().c_str(), "eng", tesseract::OEM_TESSERACT_ONLY);
   api.SetPageSegMode(tesseract::PSM_SINGLE_BLOCK);
   api.SetVariable("paragraph_debug_level", "3");
+#if 0 // TODO: b622.png is missing
   Pix* src_pix = pixRead(TestDataNameToPath("b622.png").c_str());
   CHECK(src_pix);
   api.SetImage(src_pix);
@@ -88,6 +109,7 @@ TEST_F(TesseractTest, IteratesParagraphsEvenIfNotDetected) {
   boxaDestroy(&block_boxes);
   boxaDestroy(&para_boxes);
   pixDestroy(&src_pix);
+#endif
 }
 
 // We should get hOCR output and not seg fault, even if the api caller doesn't
@@ -130,6 +152,7 @@ TEST_F(TesseractTest, HOCRContainsBaseline) {
 TEST_F(TesseractTest, RickSnyderNotFuckSnyder) {
   tesseract::TessBaseAPI api;
   api.Init(TessdataPath().c_str(), "eng", tesseract::OEM_TESSERACT_ONLY);
+#if 0 // TODO: rick_snyder.jpeg is missing
   Pix* src_pix = pixRead(TestDataNameToPath("rick_snyder.jpeg").c_str());
   CHECK(src_pix);
   api.SetImage(src_pix);
@@ -138,6 +161,7 @@ TEST_F(TesseractTest, RickSnyderNotFuckSnyder) {
   EXPECT_THAT(result, Not(HasSubstr("FUCK")));
   delete[] result;
   pixDestroy(&src_pix);
+#endif
 }
 
 // Tests that Tesseract gets exactly the right answer on some page numbers.
@@ -152,14 +176,14 @@ TEST_F(TesseractTest, AdaptToWordStrTest) {
   static const char* kTestPages[] = {"324.tif", "433.tif", "12.tif", nullptr};
   static const char* kTestText[] = {"324", "433", "12", nullptr};
   tesseract::TessBaseAPI api;
-  string truth_text;
-  string ocr_text;
+  std::string truth_text;
+  std::string ocr_text;
   api.Init(TessdataPath().c_str(), "eng", tesseract::OEM_TESSERACT_ONLY);
   api.SetVariable("matcher_sufficient_examples_for_prototyping", "1");
   api.SetVariable("classify_class_pruner_threshold", "220");
   // Train on the training text.
   for (int i = 0; kTrainingPages[i] != nullptr; ++i) {
-    string image_file = TestDataNameToPath(kTrainingPages[i]);
+    std::string image_file = TestDataNameToPath(kTrainingPages[i]);
     Pix* src_pix = pixRead(image_file.c_str());
     CHECK(src_pix);
     api.SetImage(src_pix);
@@ -185,8 +209,8 @@ TEST_F(TesseractTest, AdaptToWordStrTest) {
 // Tests that LSTM gets exactly the right answer on phototest.
 TEST_F(TesseractTest, BasicLSTMTest) {
   tesseract::TessBaseAPI api;
-  string truth_text;
-  string ocr_text;
+  std::string truth_text;
+  std::string ocr_text;
   api.Init(TessdataPath().c_str(), "eng", tesseract::OEM_LSTM_ONLY);
   Pix* src_pix = pixRead(TestDataNameToPath("phototest_2.tif").c_str());
   CHECK(src_pix);
@@ -247,7 +271,7 @@ TEST_F(TesseractTest, LSTMGeometryTest) {
 
 TEST_F(TesseractTest, InitConfigOnlyTest) {
   // Languages for testing initialization.
-  const char* langs[] = {"eng", "chi_tra", "jpn", "vie", "hin"};
+  const char* langs[] = {"eng", "chi_tra", "jpn", "vie"};
   std::unique_ptr<tesseract::TessBaseAPI> api;
   CycleTimer timer;
   for (int i = 0; i < ARRAYSIZE(langs); ++i) {
@@ -286,24 +310,24 @@ TEST(TesseractInstanceTest, TestMultipleTessInstances) {
   int num_langs = 0;
   while (langs[num_langs] != nullptr) ++num_langs;
 
-  const string kTessdataPath = file::JoinPath(FLAGS_test_srcdir, "tessdata");
+  const std::string kTessdataPath = TESSDATA_DIR;
 
   // Preload images and verify that OCR is correct on them individually.
   std::vector<Pix*> pix(num_langs);
   for (int i = 0; i < num_langs; ++i) {
     SCOPED_TRACE(absl::StrCat("Single instance test with lang = ", langs[i]));
-    string path = FLAGS_test_srcdir + "/testdata/" + image_files[i];
+    std::string path = file::JoinPath(TESTING_DIR, image_files[i]);
     pix[i] = pixRead(path.c_str());
     QCHECK(pix[i] != nullptr) << "Could not read " << path;
 
     tesseract::TessBaseAPI tess;
     EXPECT_EQ(0, tess.Init(kTessdataPath.c_str(), langs[i]));
-    string ocr_result = GetCleanedTextResult(&tess, pix[i]);
+    std::string ocr_result = GetCleanedTextResult(&tess, pix[i]);
     EXPECT_STREQ(gt_text[i], ocr_result.c_str());
   }
 
   // Process the images in all pairwise combinations of associated languages.
-  string ocr_result[2];
+  std::string ocr_result[2];
   for (int i = 0; i < num_langs; ++i) {
     for (int j = i + 1; j < num_langs; ++j) {
       tesseract::TessBaseAPI tess1, tess2;
@@ -324,21 +348,21 @@ TEST(TesseractInstanceTest, TestMultipleTessInstances) {
 
 // Tests whether Tesseract parameters are correctly set for the two instances.
 TEST(TesseractInstanceTest, TestMultipleTessInstanceVariables) {
-  string illegal_name = "an_illegal_name";
-  string langs[2] = {"eng", "hin"};
-  string int_param_name = "tessedit_pageseg_mode";
+  std::string illegal_name = "an_illegal_name";
+  std::string langs[2] = {"eng", "hin"};
+  std::string int_param_name = "tessedit_pageseg_mode";
   int int_param[2] = {1, 2};
-  string int_param_str[2] = {"1", "2"};
-  string bool_param_name = "tessedit_ambigs_training";
+  std::string int_param_str[2] = {"1", "2"};
+  std::string bool_param_name = "tessedit_ambigs_training";
   bool bool_param[2] = {false, true};
-  string bool_param_str[2] = {"F", "T"};
-  string str_param_name = "tessedit_char_blacklist";
-  string str_param[2] = {"abc", "def"};
-  string double_param_name = "segment_penalty_dict_frequent_word";
-  string double_param_str[2] = {"0.01", "2"};
+  std::string bool_param_str[2] = {"F", "T"};
+  std::string str_param_name = "tessedit_char_blacklist";
+  std::string str_param[2] = {"abc", "def"};
+  std::string double_param_name = "segment_penalty_dict_frequent_word";
+  std::string double_param_str[2] = {"0.01", "2"};
   double double_param[2] = {0.01, 2};
 
-  const string kTessdataPath = file::JoinPath(FLAGS_test_srcdir, "tessdata");
+  const std::string kTessdataPath = TESSDATA_DIR;
 
   tesseract::TessBaseAPI tess1, tess2;
   for (int i = 0; i < 2; ++i) {