Spec: try to call 'crystal i' when possible

spec/std/exception/call_stack_spec.cr

@@ -55,7 +55,7 @@ describe "Backtrace" do
     error.to_s.should contain("IndexError")
   end
 
-  it "prints crash backtrace to stderr", tags: %w[slow] do
+  pending_interpreted "prints crash backtrace to stderr", tags: %w[slow] do
     sample = datapath("crash_backtrace_sample")
 
     _, output, error = compile_and_run_file(sample)

spec/std/kernel_spec.cr

@@ -243,7 +243,7 @@ describe "at_exit" do
   end
 end
 
-describe "hardware exception" do
+pending_interpreted describe: "hardware exception" do
   it "reports invalid memory access", tags: %w[slow] do
     status, _, error = compile_and_run_source <<-'CRYSTAL'
       puts Pointer(Int64).null.value

spec/std/spec_helper.cr

@@ -78,9 +78,6 @@ def spawn_and_check(before : Proc(_), file = __FILE__, line = __LINE__, &block :
 end
 
 def compile_file(source_file, *, bin_name = "executable_file", flags = %w(), file = __FILE__, &)
-  # can't use backtick in interpreted code (#12241)
-  pending_interpreted! "Unable to compile Crystal code in interpreted code"
-
   with_temp_executable(bin_name, file: file) do |executable_file|
     compiler = ENV["CRYSTAL_SPEC_COMPILER_BIN"]? || "bin/crystal"
     args = ["build"] + flags + ["-o", executable_file, source_file]
@@ -111,12 +108,17 @@ def compile_source(source, flags = %w(), file = __FILE__, &)
 end
 
 def compile_and_run_file(source_file, flags = %w(), runtime_args = %w(), file = __FILE__)
-  compile_file(source_file, flags: flags, file: file) do |executable_file|
-    output, error = IO::Memory.new, IO::Memory.new
-    status = Process.run executable_file, args: runtime_args, output: output, error: error
-
-    {status, output.to_s, error.to_s}
-  end
+  status, output, error = Process::Status.new(0), IO::Memory.new, IO::Memory.new
+  {% if flag?(:interpreted) %}
+    compiler = ENV["CRYSTAL_SPEC_COMPILER_BIN"]? || "bin/crystal"
+    args = ["i", source_file, "--", *runtime_args]
+    status = Process.run compiler, args: args, output: output, error: error
+  {% else %}
+    compile_file(source_file, flags: flags, file: file) do |executable_file|
+      status = Process.run executable_file, args: runtime_args, output: output, error: error
+    end
+  {% end %}
+  {status, output.to_s, error.to_s}
 end
 
 def compile_and_run_source(source, flags = %w(), runtime_args = %w(), file = __FILE__)

spec/support/interpreted.cr

@@ -1,8 +1,8 @@
 require "spec"
 
 {% if flag?(:interpreted) %}
-  def pending_interpreted(description = "assert", file = __FILE__, line = __LINE__, end_line = __END_LINE__, &block)
-    pending("#{description} [interpreted]", file, line, end_line)
+  def pending_interpreted(description = "assert", file = __FILE__, line = __LINE__, end_line = __END_LINE__, tags = nil, &block)
+    pending("#{description} [interpreted]", file, line, end_line, false, tags)
   end
 
   def pending_interpreted(*, describe, file = __FILE__, line = __LINE__, end_line = __END_LINE__, &block)