diff --git a/idlc/test/parser/conversion.tests b/idlc/test/parser/conversion.tests
index 4f1d6bc7d3e9..4b9aede89a70 100644
--- a/idlc/test/parser/conversion.tests
+++ b/idlc/test/parser/conversion.tests
@@ -6,74 +6,23 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 #
 
-EXPECT SUCCESS "conversion.tests 1":
-constants C {
-    const byte C1 = -128.0;
-    const byte C2 = -127.9;
-    const byte C3 = 254.9;
-    const byte C4 = 255.0;
-    const short C5 = -32768.0;
-    const short C6 = -32767.9;
-    const short C7 = 32766.9;
-    const short C8 = 32767.0;
-    const unsigned short C9 = 0.0;
-    const unsigned short C10 = 0.1;
-    const unsigned short C11 = 65534.9;
-    const unsigned short C12 = 65535.0;
-    const long C13 = -2147483648.0;
-    const long C14 = -2147483647.9;
-    const long C15 = 2147483646.9;
-    const long C16 = 2147483647.0;
-    const unsigned long C17 = 0.0;
-    const unsigned long C18 = 0.1;
-    const unsigned long C19 = 4294967294.9;
-    const unsigned long C20 = 4294967295.0;
-    const hyper C21 = -9223372036854774784.0; // -0x7FFFFFFFFFFFFC00 = -0x1.FFFFFFFFFFFFFp62
-    const hyper C22 = 9223372036854774784.0; // 0x7FFFFFFFFFFFFC00 = 0x1.FFFFFFFFFFFFFp62
-    const unsigned hyper C23 = 0.0;
-    const unsigned hyper C24 = 0.1;
-    const unsigned hyper C25 = 18446744073709549568.0; // 0xFFFFFFFFFFFFF800 = 0x1.FFFFFFFFFFFFFp63
-};
+EXPECT FAILURE "conversion.tests 1":
+constants C { const byte C1 = 0.0; };
 
 EXPECT FAILURE "conversion.tests 2":
-constants C { const byte C1 = -128.1; };
+constants C { const short C1 = 0.0; };
 
 EXPECT FAILURE "conversion.tests 3":
-constants C { const byte C1 = 255.1; };
+constants C { const unsigned short C1 = 0.0; };
 
 EXPECT FAILURE "conversion.tests 4":
-constants C { const short C1 = -32768.1; };
+constants C { const long C1 = 0.0; };
 
 EXPECT FAILURE "conversion.tests 5":
-constants C { const short C1 = 32767.1; };
+constants C { const unsigned long C1 = 0.0; };
 
 EXPECT FAILURE "conversion.tests 6":
-constants C { const unsigned short C1 = -0.1; };
+constants C { const hyper C1 = 0.0; };
 
 EXPECT FAILURE "conversion.tests 7":
-constants C { const unsigned short C1 = 65535.1; };
-
-EXPECT FAILURE "conversion.tests 8":
-constants C { const long C1 = -2147483648.1; };
-
-EXPECT FAILURE "conversion.tests 9":
-constants C { const long C1 = 2147483647.1; };
-
-EXPECT FAILURE "conversion.tests 10":
-constants C { const unsigned long C1 = -0.1; };
-
-EXPECT FAILURE "conversion.tests 11":
-constants C { const unsigned long C1 = 4294967295.1; };
-
-EXPECT FAILURE "conversion.tests 12":
-constants C { const hyper C1 = -9223372036854775808.0; }; // -0x8000000000000000 = -0x1p63
-
-EXPECT FAILURE "conversion.tests 13":
-constants C { const hyper C1 = 9223372036854775807.0; }; // 0x7FFFFFFFFFFFFFFF rounds up to 0x1p63
-
-EXPECT FAILURE "conversion.tests 14":
-constants C { const unsigned hyper C1 = -0.1; };
-
-EXPECT FAILURE "conversion.tests 15":
-constants C { const unsigned hyper C1 = 18446744073709551615.0; };
-    // 0xFFFFFFFFFFFFFFFF rounds up to 0x1p64
+constants C { const unsigned hyper C1 = 0.0; };
diff --git a/unoidl/CustomTarget_unoidl-write_test.mk b/unoidl/CustomTarget_unoidl-write_test.mk
index a1c17c488bc3..fc80f516c53d 100644
--- a/unoidl/CustomTarget_unoidl-write_test.mk
+++ b/unoidl/CustomTarget_unoidl-write_test.mk
@@ -18,6 +18,7 @@ $(call gb_CustomTarget_get_target,unoidl/unoidl-write_test) : \
         $(SRCDIR)/idlc/test/parser/attribute.tests \
         $(SRCDIR)/idlc/test/parser/constant.tests \
         $(SRCDIR)/idlc/test/parser/constructor.tests \
+        $(SRCDIR)/idlc/test/parser/conversion.tests \
         $(SRCDIR)/idlc/test/parser/interfaceinheritance.tests \
         $(SRCDIR)/idlc/test/parser/methodoverload.tests \
         $(SRCDIR)/idlc/test/parser/polystruct.tests \
@@ -47,6 +48,12 @@ else
             1 $(call gb_Executable_get_command,unoidl-write) $(SRCDIR)/udkapi \
             {} \
             $(call gb_CustomTarget_get_workdir,unoidl/unoidl-write_test)/out.rdb \
+        && $(PERL) $(SRCDIR)/solenv/bin/exectest.pl \
+            $(SRCDIR)/idlc/test/parser/conversion.tests \
+            $(call gb_CustomTarget_get_workdir,unoidl/unoidl-write_test)/in.idl \
+            1 $(call gb_Executable_get_command,unoidl-write) $(SRCDIR)/udkapi \
+            {} \
+            $(call gb_CustomTarget_get_workdir,unoidl/unoidl-write_test)/out.rdb \
         && $(PERL) $(SRCDIR)/solenv/bin/exectest.pl \
             $(SRCDIR)/idlc/test/parser/interfaceinheritance.tests \
             $(call gb_CustomTarget_get_workdir,unoidl/unoidl-write_test)/in.idl \