In tests: Use $::env(DESIGN_TOP) where it isn't already.

This makes all tests use the same concept for accessing the
test verilog file in question. It also makes it possible to
run tests from different directories if only DESIGN_TOP is set
correctly.

In one place, a filename is resolved intended relative to the script,
but currently requires the script to be executed in the same
directory; make that location independent by reading it
relative to [file dirname [info script]]

Signed-off-by: Henner Zeller <h.zeller@acm.org>
diff --git a/design_introspection-plugin/tests/get_cells/get_cells.tcl b/design_introspection-plugin/tests/get_cells/get_cells.tcl
index 85cc897..4302b73 100644
--- a/design_introspection-plugin/tests/get_cells/get_cells.tcl
+++ b/design_introspection-plugin/tests/get_cells/get_cells.tcl
@@ -3,7 +3,7 @@
 #Import the commands from the plugins to the tcl interpreter
 yosys -import
 
-read_verilog get_cells.v
+read_verilog $::env(DESIGN_TOP).v
 # Some of symbiflow expects eblifs with only one module.
 synth_xilinx -flatten -abc9 -nosrl -noclkbuf -nodsp
 
diff --git a/design_introspection-plugin/tests/get_nets/get_nets.tcl b/design_introspection-plugin/tests/get_nets/get_nets.tcl
index 2d3083a..93304bf 100644
--- a/design_introspection-plugin/tests/get_nets/get_nets.tcl
+++ b/design_introspection-plugin/tests/get_nets/get_nets.tcl
@@ -3,7 +3,7 @@
 #Import the commands from the plugins to the tcl interpreter
 yosys -import
 
-read_verilog get_nets.v
+read_verilog $::env(DESIGN_TOP).v
 # Some of symbiflow expects eblifs with only one module.
 synth_xilinx -flatten -abc9 -nosrl -noclkbuf -nodsp
 
diff --git a/design_introspection-plugin/tests/get_pins/get_pins.tcl b/design_introspection-plugin/tests/get_pins/get_pins.tcl
index e352df1..b2efcdc 100644
--- a/design_introspection-plugin/tests/get_pins/get_pins.tcl
+++ b/design_introspection-plugin/tests/get_pins/get_pins.tcl
@@ -3,7 +3,7 @@
 #Import the commands from the plugins to the tcl interpreter
 yosys -import
 
-read_verilog get_pins.v
+read_verilog $::env(DESIGN_TOP).v
 # Some of symbiflow expects eblifs with only one module.
 synth_xilinx -flatten -abc9 -nosrl -noclkbuf -nodsp
 
diff --git a/design_introspection-plugin/tests/get_ports/get_ports.tcl b/design_introspection-plugin/tests/get_ports/get_ports.tcl
index f82305a..71df0a0 100644
--- a/design_introspection-plugin/tests/get_ports/get_ports.tcl
+++ b/design_introspection-plugin/tests/get_ports/get_ports.tcl
@@ -3,7 +3,7 @@
 #Import the commands from the plugins to the tcl interpreter
 yosys -import
 
-read_verilog get_ports.v
+read_verilog $::env(DESIGN_TOP).v
 # Some of symbiflow expects eblifs with only one module.
 synth_xilinx -flatten -abc9 -nosrl -noclkbuf -nodsp
 help get_ports
diff --git a/get_count-plugin/tests/simple/simple.tcl b/get_count-plugin/tests/simple/simple.tcl
index f933c94..8e006c8 100644
--- a/get_count-plugin/tests/simple/simple.tcl
+++ b/get_count-plugin/tests/simple/simple.tcl
@@ -1,7 +1,7 @@
 yosys plugin -i get_count
 yosys -import
 
-read_verilog -icells simple.v
+read_verilog -icells $::env(DESIGN_TOP).v
 hierarchy -auto-top
 
 set n [get_count -modules my_gate]
diff --git a/sdc-plugin/tests/set_clock_groups/set_clock_groups.tcl b/sdc-plugin/tests/set_clock_groups/set_clock_groups.tcl
index 223d9ec..43445c7 100644
--- a/sdc-plugin/tests/set_clock_groups/set_clock_groups.tcl
+++ b/sdc-plugin/tests/set_clock_groups/set_clock_groups.tcl
@@ -3,7 +3,7 @@
 #Import the commands from the plugins to the tcl interpreter
 yosys -import
 
-read_verilog set_clock_groups.v
+read_verilog $::env(DESIGN_TOP).v
 # Some of symbiflow expects eblifs with only one module.
 synth_xilinx -flatten -abc9 -nosrl -noclkbuf -nodsp
 
diff --git a/selection-plugin/tests/counter/counter.tcl b/selection-plugin/tests/counter/counter.tcl
index 5475822..2411f8f 100644
--- a/selection-plugin/tests/counter/counter.tcl
+++ b/selection-plugin/tests/counter/counter.tcl
@@ -27,7 +27,7 @@
     }
 }
 
-read_verilog counter.v
+read_verilog $::env(DESIGN_TOP).v
 read_verilog -specify -lib -D_EXPLICIT_CARRY +/xilinx/cells_sim.v
 read_verilog -lib +/xilinx/cells_xtra.v
 hierarchy -check -auto-top
diff --git a/xdc-plugin/tests/minilitex_ddr_arty/minilitex_ddr_arty.tcl b/xdc-plugin/tests/minilitex_ddr_arty/minilitex_ddr_arty.tcl
index fe1c07c..e347909 100644
--- a/xdc-plugin/tests/minilitex_ddr_arty/minilitex_ddr_arty.tcl
+++ b/xdc-plugin/tests/minilitex_ddr_arty/minilitex_ddr_arty.tcl
@@ -5,7 +5,7 @@
 yosys -import
 
 read_verilog $::env(DESIGN_TOP).v
-read_verilog VexRiscv_Lite.v
+read_verilog [file dirname [info script]]/VexRiscv_Lite.v
 # -flatten is used to ensure that the output eblif has only one module.
 # Some of symbiflow expects eblifs with only one module.
 synth_xilinx -flatten -abc9 -nosrl -noclkbuf -nodsp