5 files changed, 45 insertions, 14 deletions
diff --git a/spec/mspec/lib/mspec/helpers/datetime.rb b/spec/mspec/lib/mspec/helpers/datetime.rb
index 3a40cc0902..84ac86b686 100644
--- a/spec/mspec/lib/mspec/helpers/datetime.rb
+++ b/spec/mspec/lib/mspec/helpers/datetime.rb
@@ -25,6 +25,7 @@ def new_datetime(opts = {})
 end
 
 def with_timezone(name, offset = nil, daylight_saving_zone = "")
+  skip "WASI doesn't have TZ concept" if PlatformGuard.wasi?
   zone = name.dup
 
   if offset
diff --git a/spec/mspec/lib/mspec/helpers/io.rb b/spec/mspec/lib/mspec/helpers/io.rb
index 29c6c37a1a..2ad14f47a1 100644
--- a/spec/mspec/lib/mspec/helpers/io.rb
+++ b/spec/mspec/lib/mspec/helpers/io.rb
@@ -7,7 +7,7 @@ class IOStub
   end
 
   def write(*str)
-    self << str.join
+    self << str.join('')
   end
 
   def << str
@@ -16,7 +16,7 @@ class IOStub
   end
 
   def print(*str)
-    write(str.join + $\.to_s)
+    write(str.join('') + $\.to_s)
   end
 
   def method_missing(name, *args, &block)
diff --git a/spec/mspec/lib/mspec/helpers/numeric.rb b/spec/mspec/lib/mspec/helpers/numeric.rb
index db1fde64d8..c1ed81a233 100644
--- a/spec/mspec/lib/mspec/helpers/numeric.rb
+++ b/spec/mspec/lib/mspec/helpers/numeric.rb
@@ -9,7 +9,9 @@ def infinity_value
 end
 
 def bignum_value(plus = 0)
-  0x8000_0000_0000_0000 + plus
+  # Must be >= fixnum_max + 2, so -bignum_value is < fixnum_min
+  # A fixed value has the advantage to be the same numeric value for all Rubies and is much easier to spec
+  (2**64) + plus
 end
 
 def max_long
diff --git a/spec/mspec/lib/mspec/helpers/ruby_exe.rb b/spec/mspec/lib/mspec/helpers/ruby_exe.rb
index 4948ec09f1..2e499d6f9a 100644
--- a/spec/mspec/lib/mspec/helpers/ruby_exe.rb
+++ b/spec/mspec/lib/mspec/helpers/ruby_exe.rb
@@ -112,6 +112,8 @@ unless Object.const_defined?(:RUBY_EXE) and RUBY_EXE
 end
 
 def ruby_exe(code = :not_given, opts = {})
+  skip "WASI doesn't provide subprocess" if PlatformGuard.wasi?
+
   if opts[:dir]
     raise "ruby_exe(..., dir: dir) is no longer supported, use Dir.chdir"
   end
@@ -138,19 +140,44 @@ def ruby_exe(code = :not_given, opts = {})
   expected_status = opts.fetch(:exit_status, 0)
 
   begin
-    platform_is_not :opal do
-      command = ruby_cmd(code, opts)
-      output = `#{command}`
-
-      exit_status = Process.last_status.exitstatus
-      if exit_status != expected_status
-        formatted_output = output.lines.map { |line| "  #{line}" }.join
-        raise SpecExpectationNotMetError,
-          "Expected exit status is #{expected_status.inspect} but actual is #{exit_status.inspect} for command ruby_exe(#{command.inspect})\nOutput:\n#{formatted_output}"
+    command = ruby_cmd(code, opts)
+
+    # Try to avoid the extra shell for 2>&1
+    # This is notably useful for TimeoutAction which can then signal the ruby subprocess and not the shell
+    popen_options = []
+    if command.end_with?(' 2>&1')
+      command = command[0...-5]
+      popen_options = [{ err: [:child, :out] }]
+    end
+
+    output = IO.popen(command, *popen_options) do |io|
+      pid = io.pid
+      MSpec.subprocesses << pid
+      begin
+        io.read
+      ensure
+        MSpec.subprocesses.delete(pid)
       end
+    end
 
-      output
+    status = Process.last_status
+
+    exit_status = if status.exited?
+                    status.exitstatus
+                  elsif status.signaled?
+                    signame = Signal.signame status.termsig
+                    raise "No signal name?" unless signame
+                    :"SIG#{signame}"
+                  else
+                    raise SpecExpectationNotMetError, "#{exit_status.inspect} is neither exited? nor signaled?"
+                  end
+    if exit_status != expected_status
+      formatted_output = output.lines.map { |line| "  #{line}" }.join
+      raise SpecExpectationNotMetError,
+        "Expected exit status is #{expected_status.inspect} but actual is #{exit_status.inspect} for command ruby_exe(#{command.inspect})\nOutput:\n#{formatted_output}"
     end
+
+    output
   ensure
     saved_env.each { |key, value| ENV[key] = value }
     env.keys.each do |key|
diff --git a/spec/mspec/lib/mspec/helpers/tmp.rb b/spec/mspec/lib/mspec/helpers/tmp.rb
index b2a38ee983..4c0eddab75 100644
--- a/spec/mspec/lib/mspec/helpers/tmp.rb
+++ b/spec/mspec/lib/mspec/helpers/tmp.rb
@@ -12,7 +12,7 @@ else
 end
 SPEC_TEMP_DIR = spec_temp_dir
 
-SPEC_TEMP_UNIQUIFIER = "0"
+SPEC_TEMP_UNIQUIFIER = +"0"
 
 at_exit do
   begin
@@ -41,6 +41,7 @@ def tmp(name, uniquify = true)
   if uniquify and !name.empty?
     slash = name.rindex "/"
     index = slash ? slash + 1 : 0
+    name = +name
     name.insert index, "#{SPEC_TEMP_UNIQUIFIER.succ!}-"
   end