diff --git a/src/bin/d2/tests/d2_cfg_mgr_unittests.cc b/src/bin/d2/tests/d2_cfg_mgr_unittests.cc
index 876a8795868adbae7c63684a1c7e1d3342796a4c..a2c901234ec4aacb5cb743f954ce22e0ece59463 100644
--- a/src/bin/d2/tests/d2_cfg_mgr_unittests.cc
+++ b/src/bin/d2/tests/d2_cfg_mgr_unittests.cc
@@ -418,7 +418,7 @@ TEST_F(D2CfgMgrTest, invalidEntry) {
     // Unsupported protocol
     config = makeParamsConfigString ("127.0.0.1", 777, 333, "TCP", "JSON");
     LOGIC_ERROR(config, "ncr-protocol : TCP is not yet supported"
-                        "  (<string>:1:92)");
+                        " (<string>:1:92)");
 
     // Invalid format
     config = makeParamsConfigString ("127.0.0.1", 777, 333, "UDP", "BOGUS");
diff --git a/src/bin/d2/tests/d2_process_unittests.cc b/src/bin/d2/tests/d2_process_unittests.cc
index 73936e5bb05d8e8c8caa112ce0578b33df7e9334..2af2b3021d87a1df556a92b338e2c64f40e44066 100644
--- a/src/bin/d2/tests/d2_process_unittests.cc
+++ b/src/bin/d2/tests/d2_process_unittests.cc
@@ -101,7 +101,7 @@ public:
 
         if (rcode) {
             return (::testing::AssertionFailure(::testing::Message() <<
-                                                "configure() failed:"
+                                                "configure() failed: "
                                                 << comment));
         }
 
diff --git a/src/bin/d2/tests/testdata/d2_cfg_tests.json b/src/bin/d2/tests/testdata/d2_cfg_tests.json
index c90a788eb93f4b1ea47ee89bfbee3f32fcc4ebd4..f836d996bdb20d147018d1c20996c065a9ff6d9c 100644
--- a/src/bin/d2/tests/testdata/d2_cfg_tests.json
+++ b/src/bin/d2/tests/testdata/d2_cfg_tests.json
@@ -240,7 +240,7 @@
 #-----
 ,{
 "description" : "D2Params.ncr-protocol, unsupported TCP",
-"logic-error" : "ncr-protocol : TCP is not yet supported  (<string>:1:41)",
+"logic-error" : "ncr-protocol : TCP is not yet supported (<string>:1:41)",
 "data" :
     {
     "ncr-protocol" : "TCP",
@@ -545,7 +545,7 @@
 #-----
 ,{
 "description" : "D2.tsig-keys, too small truncated HMAC-MD5",
-"logic-error" : "tsig-key: digest-bits too small :  (<string>:1:104)",
+"logic-error" : "tsig-key: digest-bits too small : (<string>:1:104)",
 "data" :
     {
     "forward-ddns" : {},
@@ -565,7 +565,7 @@
 #-----
 ,{
 "description" : "D2.tsig-keys, too small truncated HMAC-SHA1",
-"logic-error" : "tsig-key: digest-bits too small :  (<string>:1:105)",
+"logic-error" : "tsig-key: digest-bits too small : (<string>:1:105)",
 "data" :
     {
     "forward-ddns" : {},
@@ -585,7 +585,7 @@
 #-----
 ,{
 "description" : "D2.tsig-keys, too small truncated HMAC-SHA224",
-"logic-error" : "tsig-key: digest-bits too small :  (<string>:1:107)",
+"logic-error" : "tsig-key: digest-bits too small : (<string>:1:107)",
 "data" :
     {
     "forward-ddns" : {},
@@ -605,7 +605,7 @@
 #-----
 ,{
 "description" : "D2.tsig-keys, too small truncated HMAC-SHA256",
-"logic-error" : "tsig-key: digest-bits too small :  (<string>:1:107)",
+"logic-error" : "tsig-key: digest-bits too small : (<string>:1:107)",
 "data" :
     {
     "forward-ddns" : {},
@@ -625,7 +625,7 @@
 #-----
 ,{
 "description" : "D2.tsig-keys, too small truncated HMAC-SHA384",
-"logic-error" : "tsig-key: digest-bits too small :  (<string>:1:107)",
+"logic-error" : "tsig-key: digest-bits too small : (<string>:1:107)",
 "data" :
     {
     "forward-ddns" : {},
@@ -645,7 +645,7 @@
 #-----
 ,{
 "description" : "D2.tsig-keys, too small truncated HMAC-SHA512",
-"logic-error" : "tsig-key: digest-bits too small :  (<string>:1:107)",
+"logic-error" : "tsig-key: digest-bits too small : (<string>:1:107)",
 "data" :
     {
     "forward-ddns" : {},
diff --git a/src/lib/cql/testutils/cql_schema.cc b/src/lib/cql/testutils/cql_schema.cc
index 4dff591c5a93aabb0a9a44b31c92033b23b997bc..f4b3b137650459b7c0c793dd6829203a2a0c6746 100644
--- a/src/lib/cql/testutils/cql_schema.cc
+++ b/src/lib/cql/testutils/cql_schema.cc
@@ -68,8 +68,8 @@ runCqlScript(const std::string& path,
 
     int32_t retval = ::system(cmd.str().c_str());
     if (retval) {
-        std::cerr << "runCqlSchema failed:" << cmd.str() << std::endl;
-        isc_throw(Unexpected, "runCqlSchema failed:" << cmd.str());
+        std::cerr << "runCqlSchema failed: " << cmd.str() << std::endl;
+        isc_throw(Unexpected, "runCqlSchema failed: " << cmd.str());
     }
 }
 
diff --git a/src/lib/dhcpsrv/tests/pgsql_host_data_source_unittest.cc b/src/lib/dhcpsrv/tests/pgsql_host_data_source_unittest.cc
index a33a2434aff2271975f6dd71d0b7210421a4aaf0..3ca49bc04c7cb2114509d3d4a6f3a6020e0c7df2 100644
--- a/src/lib/dhcpsrv/tests/pgsql_host_data_source_unittest.cc
+++ b/src/lib/dhcpsrv/tests/pgsql_host_data_source_unittest.cc
@@ -128,7 +128,7 @@ public:
 
         PgSqlResult r(PQexec(conn, query.c_str()));
         if (PQresultStatus(r) != PGRES_TUPLES_OK) {
-            isc_throw(DbOperationError, "Query failed:" << PQerrorMessage(conn));
+            isc_throw(DbOperationError, "Query failed: " << PQerrorMessage(conn));
         }
 
         int numrows = PQntuples(r);
diff --git a/src/lib/mysql/testutils/mysql_schema.cc b/src/lib/mysql/testutils/mysql_schema.cc
index ef72313abc3cc93687f4bafc0f68908ca1eb12b6..d198bbde0e4bc03f64d0d8ebc17e7e6d680ac363 100644
--- a/src/lib/mysql/testutils/mysql_schema.cc
+++ b/src/lib/mysql/testutils/mysql_schema.cc
@@ -82,8 +82,8 @@ void runMySQLScript(const std::string& path, const std::string& script_name,
 
     int retval = ::system(cmd.str().c_str());
     if (retval) {
-        std::cerr << "runMySQLSchema failed:" << cmd.str() << std::endl;
-        isc_throw(Unexpected, "runMySQLSchema failed:" << cmd.str());
+        std::cerr << "runMySQLSchema failed: " << cmd.str() << std::endl;
+        isc_throw(Unexpected, "runMySQLSchema failed: " << cmd.str());
     }
 }
 
diff --git a/src/lib/pgsql/testutils/pgsql_schema.cc b/src/lib/pgsql/testutils/pgsql_schema.cc
index f12bcbfef76e8f1c1d77d91adb45e87173d6213a..049fadffef4adc839ba976c5eaf5d1261b541e60 100644
--- a/src/lib/pgsql/testutils/pgsql_schema.cc
+++ b/src/lib/pgsql/testutils/pgsql_schema.cc
@@ -93,8 +93,8 @@ void runPgSQLScript(const std::string& path, const std::string& script_name,
 
     int retval = ::system(cmd.str().c_str());
     if (retval) {
-        std::cerr << "runPgSQLSchema failed:" << cmd.str() << std::endl;
-        isc_throw(Unexpected, "runPgSQLSchema failed:" << cmd.str());
+        std::cerr << "runPgSQLSchema failed: " << cmd.str() << std::endl;
+        isc_throw(Unexpected, "runPgSQLSchema failed: " << cmd.str());
     }
 }
 
diff --git a/src/lib/process/testutils/d_test_stubs.cc b/src/lib/process/testutils/d_test_stubs.cc
index 300035e24f2b1ede67a6a5e7c56991049de6550f..730ac536770856089f0d73b52adf999b9f3e6bf4 100644
--- a/src/lib/process/testutils/d_test_stubs.cc
+++ b/src/lib/process/testutils/d_test_stubs.cc
@@ -47,7 +47,7 @@ DStubProcess::run() {
             io_service->run_one();
         } catch (const std::exception& ex) {
             isc_throw (DProcessBaseError,
-                std::string("Process run method failed:") + ex.what());
+                std::string("Process run method failed: ") + ex.what());
         }
     }
 };