build: require boost >= 1.71.0

Refs: #5276
Change-Id: I0f179707020fc6e0908af8aeb1d535ca3cd81410
diff --git a/tests/unit/wscript b/tests/unit/wscript
index 3fcf675..6b4e2b8 100644
--- a/tests/unit/wscript
+++ b/tests/unit/wscript
@@ -1,14 +1,15 @@
 # -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 
-top = '../../'
+top = '../..'
 
 def build(bld):
     tmpdir = 'UNIT_TESTS_TMPDIR="%s"' % bld.bldnode.make_node('tmp-files')
 
     # unit test objects
-    srcFiles = bld.path.ant_glob('**/*.cpp', excl=['main.cpp',
-                                                   '**/*-osx.t.cpp',
-                                                   '**/*-sqlite3.t.cpp'])
+    srcFiles = bld.path.ant_glob('**/*.cpp',
+                                 excl=['main.cpp',
+                                       '**/*-osx.t.cpp',
+                                       '**/*-sqlite3.t.cpp'])
 
     if bld.env['HAVE_OSX_FRAMEWORKS']:
         srcFiles += bld.path.ant_glob('**/*-osx.t.cpp')
@@ -16,16 +17,18 @@
     # In case we want to make it optional later
     srcFiles += bld.path.ant_glob('**/*-sqlite3.t.cpp')
 
-    bld.objects(target='unit-tests-objects',
-                source=srcFiles,
-                features='pch',
-                headers='unit-tests-pch.hpp',
-                use='tests-common',
-                defines=[tmpdir])
+    bld.objects(
+        target='unit-tests-objects',
+        source=srcFiles,
+        features='pch',
+        headers='unit-tests-pch.hpp',
+        use='tests-common',
+        defines=[tmpdir])
 
     # unit test binary
-    bld.program(target=top + 'unit-tests',
-                name='unit-tests',
-                source=['main.cpp'],
-                use='unit-tests-objects',
-                install_path=None)
+    bld.program(
+        target=f'{top}/unit-tests',
+        name='unit-tests',
+        source=['main.cpp'],
+        use='unit-tests-objects',
+        install_path=None)