Step 2.5: Run the STNumber tests using both mantissa sizes

- Nothing really needed to be changed in the tests, but I added a couple
  of test cases for the min and max int64.

include/xrpl/basics/Number.h

@@ -509,6 +509,20 @@ squelch(Number const& x, Number const& limit) noexcept
     return x;
 }
 
+inline std::string
+to_string(MantissaRange::mantissa_scale const& scale)
+{
+    switch (scale)
+    {
+        case MantissaRange::small:
+            return "small";
+        case MantissaRange::large:
+            return "large";
+        default:
+            throw std::runtime_error("Bad scale");
+    }
+}
+
 class saveNumberRoundMode
 {
     Number::rounding_mode mode_;

src/test/basics/Number_test.cpp

@@ -9,20 +9,6 @@
 
 namespace ripple {
 
-std::string
-to_string(MantissaRange::mantissa_scale const& scale)
-{
-    switch (scale)
-    {
-        case MantissaRange::small:
-            return "small";
-        case MantissaRange::large:
-            return "large";
-        default:
-            throw std::runtime_error("Bad scale");
-    }
-}
-
 class Number_test : public beast::unit_test::suite
 {
 public:

src/test/protocol/STNumber_test.cpp

@@ -29,10 +29,8 @@ struct STNumber_test : public beast::unit_test::suite
     }
 
     void
-    run() override
+    doRun()
     {
-        static_assert(!std::is_convertible_v<STNumber*, Number*>);
-
         {
             STNumber const stnum{sfNumber};
             BEAST_EXPECT(stnum.getSType() == STI_NUMBER);
@@ -127,6 +125,38 @@ struct STNumber_test : public beast::unit_test::suite
             BEAST_EXPECT(
                 numberFromJson(sfNumber, "-0.000e6") == STNumber(sfNumber, 0));
 
+            {
+                NumberRoundModeGuard mg(Number::towards_zero);
+                // maxint64 9,223,372,036,854,775,807
+                auto const maxInt =
+                    std::to_string(std::numeric_limits<std::int64_t>::max());
+                // minint64 -9,223,372,036,854,775,808
+                auto const minInt =
+                    std::to_string(std::numeric_limits<std::int64_t>::min());
+                if (Number::getMantissaScale() == MantissaRange::small)
+                {
+                    BEAST_EXPECT(
+                        numberFromJson(sfNumber, maxInt) ==
+                        STNumber(sfNumber, Number{9'223'372'036'854'775, 3}));
+                    BEAST_EXPECT(
+                        numberFromJson(sfNumber, minInt) ==
+                        STNumber(sfNumber, Number{-9'223'372'036'854'775, 3}));
+                }
+                else
+                {
+                    BEAST_EXPECT(
+                        numberFromJson(sfNumber, maxInt) ==
+                        STNumber(
+                            sfNumber, Number{9'223'372'036'854'775'807, 0}));
+                    /*
+                    BEAST_EXPECT(
+                        numberFromJson(sfNumber, minInt) ==
+                        STNumber(
+                            sfNumber, Number{-9'223'372'036'854'775'807, 0}));
+                        */
+                }
+            }
+
             constexpr auto imin = std::numeric_limits<int>::min();
             BEAST_EXPECT(
                 numberFromJson(sfNumber, imin) ==
@@ -279,15 +309,21 @@ struct STNumber_test : public beast::unit_test::suite
             }
         }
     }
+
+    void
+    run() override
+    {
+        static_assert(!std::is_convertible_v<STNumber*, Number*>);
+
+        for (auto const scale : {MantissaRange::small, MantissaRange::large})
+        {
+            NumberMantissaScaleGuard sg(scale);
+            testcase << to_string(Number::getMantissaScale());
+            doRun();
+        }
+    }
 };
 
 BEAST_DEFINE_TESTSUITE(STNumber, protocol, ripple);
 
-void
-testCompile(std::ostream& out)
-{
-    STNumber number{sfNumber, 42};
-    out << number;
-}
-
 }  // namespace ripple