Checked and added last two tests

tests/test_1.enfa

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+digraph {
+rankdir=LR
+in [shape=point style=invis]
+0 [color=yellow label="0"]
+1 [label="1"]
+2 [label="2"]
+3 [label="3"]
+4 [color=green shape=doublecircle label="4\np=0\nac=0"]
+2 -> 3 [label="D"]
+2 -> 3 [label="E"]
+2 -> 3 [label="F"]
+2 -> 3 [label="a"]
+2 -> 3 [label="b"]
+2 -> 3 [label="c"]
+2 -> 3 [label="d"]
+0 -> 1 [label="ε"]
+1 -> 2 [label="ε"]
+1 -> 4 [label="ε"]
+3 -> 2 [label="ε"]
+3 -> 4 [label="ε"]
+in -> 0
+}
+

tests/test_1.re

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+([DEFabcd])*

tests/test_6.enfa

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+digraph {
+rankdir=LR
+in [shape=point style=invis]
+0 [color=yellow label="0"]
+1 [label="1"]
+2 [color=green shape=doublecircle label="2\np=0\nac=0"]
+3 [label="3"]
+4 [color=green shape=doublecircle label="4\np=1\nac=1"]
+5 [label="5"]
+6 [color=green shape=doublecircle label="6\np=2\nac=2"]
+1 -> 2 [label=" "]
+1 -> 2 [label="^"]
+3 -> 4 [label=" "]
+5 -> 6 [label="-"]
+5 -> 6 [label="]"]
+5 -> 6 [label="^"]
+0 -> 1 [label="ε"]
+0 -> 3 [label="ε"]
+0 -> 5 [label="ε"]
+in -> 0
+}
+

tests/test_6.re

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+[ ^]
+[ ]
+[-]^]