From 159e2c1c0205cdc288c623ee075c7979f03ca630 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Sun, 29 Dec 2019 17:19:55 +0100
Subject: [PATCH] `ratio_text` improved to omit `den == 1` for `exp != 0`

---
 src/include/units/bits/unit_text.h  | 11 +++++++----
 test/unit_test/runtime/fmt_test.cpp | 25 +++++++++----------------
 2 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/src/include/units/bits/unit_text.h b/src/include/units/bits/unit_text.h
index c3118fac..bb8c91a2 100644
--- a/src/include/units/bits/unit_text.h
+++ b/src/include/units/bits/unit_text.h
@@ -29,21 +29,24 @@ namespace units::detail {
 template<typename Ratio>
 constexpr auto ratio_text()
 {
-  if constexpr(Ratio::num != 1 || Ratio::den != 1 || Ratio::exp != 0) {
+  if constexpr(Ratio::num == 1 && Ratio::den == 1 && Ratio::exp != 0) {
+    return basic_fixed_string("\u00D7 10") + superscript<Ratio::exp>() + basic_fixed_string(" ");
+  }
+  else if constexpr(Ratio::num != 1 || Ratio::den != 1 || Ratio::exp != 0) {
     auto txt = basic_fixed_string("[") + regular<Ratio::num>();
     if constexpr(Ratio::den == 1) {
       if constexpr(Ratio::exp == 0) {
-        return txt + basic_fixed_string("]");
+        return txt + basic_fixed_string("] ");
       }
       else {
         return txt + basic_fixed_string(" \u00D7 10") + superscript<Ratio::exp>() +
-            basic_fixed_string("]");
+            basic_fixed_string("] ");
       }
     }
     else {
       return txt + basic_fixed_string("/") + regular<Ratio::den>() +
           basic_fixed_string(" \u00D7 10") + superscript<Ratio::exp>() +
-          basic_fixed_string("]");
+          basic_fixed_string("] ");
     }
   }
   else {
diff --git a/test/unit_test/runtime/fmt_test.cpp b/test/unit_test/runtime/fmt_test.cpp
index 893a5d0b..b73b4ef0 100644
--- a/test/unit_test/runtime/fmt_test.cpp
+++ b/test/unit_test/runtime/fmt_test.cpp
@@ -298,7 +298,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
       SECTION("iostream")
       {
-        CHECK(stream.str() == "8 [1 × 10⁻²]m³");
+        CHECK(stream.str() == "8 × 10⁻² m³");
       }
 
       SECTION("fmt with default format {} on a quantity")
@@ -319,7 +319,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
       SECTION("iostream")
       {
-        CHECK(stream.str() == "2 [6 × 10¹]Hz");
+        CHECK(stream.str() == "2 [6 × 10¹] Hz");
       }
 
       SECTION("fmt with default format {} on a quantity")
@@ -340,7 +340,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
       SECTION("iostream")
       {
-        CHECK(stream.str() == "10 [1/6 × 10⁻¹]W");
+        CHECK(stream.str() == "10 [1/6 × 10⁻¹] W");
       }
 
       SECTION("fmt with default format {} on a quantity")
@@ -361,7 +361,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
       SECTION("iostream")
       {
-        CHECK(stream.str() == "30 [1/6 × 10²]W");
+        CHECK(stream.str() == "30 [1/6 × 10²] W");
       }
 
       SECTION("fmt with default format {} on a quantity")
@@ -430,7 +430,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
       SECTION("iostream")
       {
-        CHECK(stream.str() == "8 [1 × 10³]m⋅s");
+        CHECK(stream.str() == "8 × 10³ m⋅s");
       }
 
       SECTION("fmt with default format {} on a quantity")
@@ -451,7 +451,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
       SECTION("iostream")
       {
-        CHECK(stream.str() == "2 [6 × 10¹]kg/s");
+        CHECK(stream.str() == "2 [6 × 10¹] kg/s");
       }
 
       SECTION("fmt with default format {} on a quantity")
@@ -472,7 +472,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
       SECTION("iostream")
       {
-        CHECK(stream.str() == "10 [1/6 × 10⁻¹]kg/s");
+        CHECK(stream.str() == "10 [1/6 × 10⁻¹] kg/s");
       }
 
       SECTION("fmt with default format {} on a quantity")
@@ -493,7 +493,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
         SECTION("iostream")
         {
-          CHECK(stream.str() == "8 [1 × 10⁵]cm⋅g⋅s");
+          CHECK(stream.str() == "8 × 10⁵ cm⋅g⋅s");
         }
 
         SECTION("fmt with default format {} on a quantity")
@@ -514,7 +514,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
       SECTION("iostream")
       {
-        CHECK(stream.str() == "30 [6 × 10⁻²]1/m⋅s");
+        CHECK(stream.str() == "30 [6 × 10⁻²] 1/m⋅s");
       }
 
       SECTION("fmt with default format {} on a quantity")
@@ -934,10 +934,3 @@ TEST_CASE("quantity_cast", "[text][ostream]")
     }
   }
 }
-
-// Giving a precision specification
-// in the chrono-format-spec is valid only for std::chrono::duration types where the representation type Rep
-// is a floating-point type. For all other Rep types, a format_error shall be thrown if the chrono-format-spec
-// contains a precision specification.
-
- // string s = format("{:=>8}", 42ms); // value of s is "====42ms"