diff --git a/src/testdir/test_expr.vim b/src/testdir/test_expr.vim
index 6f1de59..11ca288 100644
--- a/src/testdir/test_expr.vim
+++ b/src/testdir/test_expr.vim
@@ -154,13 +154,22 @@
   call assert_equal(' 123', printf('%  d', 123))
   call assert_equal('-123', printf('% d', -123))
 
+  call assert_equal('123', printf('%2d', 123))
+  call assert_equal('   123', printf('%6d', 123))
+  call assert_equal('000123', printf('%06d', 123))
+  call assert_equal('+00123', printf('%+06d', 123))
+  call assert_equal(' 00123', printf('% 06d', 123))
+  call assert_equal('  +123', printf('%+6d', 123))
+  call assert_equal('   123', printf('% 6d', 123))
+  call assert_equal('  -123', printf('% 6d', -123))
+  call assert_equal('+123  ', printf('%-+6d', 123))
+  call assert_equal(' 123  ', printf('%- 6d', 123))
+  call assert_equal('-123  ', printf('%- 6d', -123))
+
   call assert_equal('00123', printf('%.*d', 5, 123))
   call assert_equal('  123', printf('% *d', 5, 123))
   call assert_equal(' +123', printf('%+ *d', 5, 123))
 
-  call assert_equal('123', printf('%2d', 123))
-  call assert_equal('  123', printf('%5d', 123))
-  call assert_equal('00123', printf('%05d', 123))
   call assert_equal('123  ', printf('%-5d', 123))
   call assert_equal('0x7b', printf('%#x', 123))
   call assert_equal('0X7B', printf('%#X', 123))
@@ -194,20 +203,81 @@
   if has('float')
     call assert_equal('1.230000', printf('%f', 1.23))
     call assert_equal('1.230000', printf('%F', 1.23))
-    call assert_equal('1.23', printf('%g', 1.23))
-    call assert_equal('1.23', printf('%G', 1.23))
+    call assert_equal('9999999.9', printf('%g', 9999999.9))
+    call assert_equal('9999999.9', printf('%G', 9999999.9))
+    call assert_equal('1.00000001e7', printf('%.8g', 10000000.1))
+    call assert_equal('1.00000001E7', printf('%.8G', 10000000.1))
     call assert_equal('1.230000e+00', printf('%e', 1.23))
     call assert_equal('1.230000E+00', printf('%E', 1.23))
     call assert_equal('1.200000e-02', printf('%e', 0.012))
     call assert_equal('-1.200000e-02', printf('%e', -0.012))
-    call assert_equal('1.2', printf('%.1f', 1.23))
+    call assert_equal('0.33', printf('%.2f', 1.0/3.0))
+    call assert_equal('  0.33', printf('%6.2f', 1.0/3.0))
+    call assert_equal(' -0.33', printf('%6.2f', -1.0/3.0))
+    call assert_equal('000.33', printf('%06.2f', 1.0/3.0))
+    " FIXME: call assert_equal('-00.33', printf('%06.2f', -1.0/3.0))
+    " FIXME: call assert_equal('-00.33', printf('%+06.2f', -1.0/3.0))
+    " FIXME: call assert_equal('+00.33', printf('%+06.2f', 1.0/3.0))
+    " FIXME: call assert_equal(' 00.33', printf('% 06.2f', 1.0/3.0))
 
+    " Float infinity can be signed.
     call assert_equal('inf', printf('%f', 1.0/0.0))
+    call assert_equal('-inf', printf('%f', -1.0/0.0))
+    call assert_equal('inf', printf('%g', 1.0/0.0))
+    call assert_equal('-inf', printf('%g', -1.0/0.0))
+    call assert_equal('inf', printf('%e', 1.0/0.0))
+    call assert_equal('-inf', printf('%e', -1.0/0.0))
+    call assert_equal('INF', printf('%E', 1.0/0.0))
+    call assert_equal('-INF', printf('%E', -1.0/0.0))
+    call assert_equal('INF', printf('%E', 1.0/0.0))
+    call assert_equal('-INF', printf('%G', -1.0/0.0))
+    call assert_equal('+inf', printf('%+f', 1.0/0.0))
+    call assert_equal('-inf', printf('%+f', -1.0/0.0))
+    call assert_equal(' inf', printf('% f',  1.0/0.0))
+    call assert_equal('   inf', printf('%6f', 1.0/0.0))
+    call assert_equal('  -inf', printf('%6f', -1.0/0.0))
+    call assert_equal('   inf', printf('%6g', 1.0/0.0))
+    call assert_equal('  -inf', printf('%6g', -1.0/0.0))
+    call assert_equal('  +inf', printf('%+6f', 1.0/0.0))
+    call assert_equal('   inf', printf('% 6f', 1.0/0.0))
+    call assert_equal('  +inf', printf('%+06f', 1.0/0.0))
+    call assert_equal('inf   ', printf('%-6f', 1.0/0.0))
+    call assert_equal('-inf  ', printf('%-6f', -1.0/0.0))
+    call assert_equal('+inf  ', printf('%-+6f', 1.0/0.0))
+    call assert_equal(' inf  ', printf('%- 6f', 1.0/0.0))
+    call assert_equal('INF   ', printf('%-6G', 1.0/0.0))
+    call assert_equal('-INF  ', printf('%-6G', -1.0/0.0))
+    call assert_equal('INF   ', printf('%-6E', 1.0/0.0))
+    call assert_equal('-INF  ', printf('%-6E', -1.0/0.0))
+    call assert_equal('inf', printf('%s', 1.0/0.0))
+    call assert_equal('-inf', printf('%s', -1.0/0.0))
 
-    call assert_match('^-inf$', printf('%f', -1.0/0.0))
+    " Float zero can be signed.
+    call assert_equal('0.000000', printf('%f', 1.0/(1.0/0.0)))
+    call assert_equal('-0.000000', printf('%f', 1.0/(-1.0/0.0)))
+    call assert_equal('0.0', printf('%s', 1.0/(1.0/0.0)))
+    call assert_equal('-0.0', printf('%s', 1.0/(-1.0/0.0)))
+    call assert_equal('0.0', printf('%S', 1.0/(1.0/0.0)))
+    call assert_equal('-0.0', printf('%S', 1.0/(-1.0/0.0)))
 
-    call assert_match('^nan$', printf('%f', sqrt(-1.0)))
-    call assert_match('^nan$', printf('%f', 0.0/0.0))
+    " Float nan (not a number) has no sign.
+    call assert_equal('nan', printf('%f', sqrt(-1.0)))
+    call assert_equal('nan', printf('%f', 0.0/0.0))
+    call assert_equal('nan', printf('%f', -0.0/0.0))
+    call assert_equal('nan', printf('%g', 0.0/0.0))
+    call assert_equal('nan', printf('%e', 0.0/0.0))
+    call assert_equal('NAN', printf('%G', 0.0/0.0))
+    call assert_equal('NAN', printf('%E', 0.0/0.0))
+    call assert_equal('NAN', printf('%G', -0.0/0.0))
+    call assert_equal('NAN', printf('%E', -0.0/0.0))
+    call assert_equal('   nan', printf('%6f', 0.0/0.0))
+    call assert_equal('   nan', printf('%06f', 0.0/0.0))
+    call assert_equal('nan   ', printf('%-6f', 0.0/0.0))
+    call assert_equal('nan   ', printf('%- 6f', 0.0/0.0))
+    call assert_equal('nan', printf('%s', 0.0/0.0))
+    call assert_equal('nan', printf('%s', -0.0/0.0))
+    call assert_equal('nan', printf('%S', 0.0/0.0))
+    call assert_equal('nan', printf('%S', -0.0/0.0))
 
     call assert_fails('echo printf("%f", "a")', 'E807:')
   endif